Hello, I would like to ask for help regarding the current vintage metagame and sideboarding for said metagame.

Here is my sideboard from a grixis control deck:
1x Flusterstorm
4x Grafdigger's Cage
3x Ingot Chewer
1x Mountain
1x Notion Thief
1x Pyroblast
1x Ravenous Trap
1x Toxic Deluge
2x Viashino Heretic

It is my understanding that the biggest decks in vintage right now are workshops, eldrazi, mentor, dredge, and misc. blue decks. So my question is what is the right amount of creature removal spells for these decks(I also have 3 creature removal spells in the mainboard). How many artifact removal cards, if any, do I bring in against eldrazi, what is the best dredge removal sweep, is it worth sideboarding against other blue decks?

You can't build a sideboard without a maindeck.

For example, the sideboard Mountain could be extraneous if you have a really solid manabase, or you might need even more land in the sideboard.

Ravenous Trap is very weak vs Dredge unless you're a relatively combo-ish deck, in which case Cage would be questionable.

I like to do the following and think about how many cards I am taking out in each matchup and then try to build my sideboard from the amount of cards i have slots to bring in for against various things. This also colors what cards I am putting in the sideboard, because generally i need more total cards than there are slots in a sideboard, so cards have to do double duty (containment priest vs oath and dredge) as an example. I know other people do it different ways.

@brassman has an interesting method where he tries out "ideal 60 card versions" of the deck against each bad matchup and then tries to make his deck modifiable from there.

Pretty sure this is the SB to the Steel City Vault type Dark Confidant Control/Combo deck he was just working on.

You might want to start by just going to mtgtop8.com and perusing the commonly played SB cards in vintage.... PS what is your plan against Dredge?

@Topical_Island I have 4 cage, ravenous trap, and toxic deluge, 6 cards. Do you think that's enough or should I go up to 7

@garbageaggro I like this method, I'll try it, thank you, but what are the cards to bring in against eldrazi and mentor? Is sudden shock good, or are board whipes better? What beats eldrazi, just random creature removal?

@dragoscar Firstly, I don't think I'm very good at sideboarding. It's just not a strength, and I think it's one of the more difficult skills in general. That said, here's what I see working for me and other people.

Firstly, make a definite determination about what you think your metagame is/will be. Think about it mathematically. How much of the field do you think will be what archetype, and also what decks are you good against and what decks are you bad against to begin with? I am sure that this is what really good players are doing... estimating the odds of seeing each type of deck and the odds of beating each of those deck with main board cards, so that they know where to focus their efforts in the sideboard. This is what I try to do... I'm not good at it, but I try.

If that's good and you're comfortable, a third thing you can think about is how much the potential hate cards will damage the opposing deck. (For example, when I board against dredge I try to have a lot of bullets, since it usually takes multiple hate cards to really kill off that deck... against Shops, I run fewer hate cards, but ones that are in my opinion, crushing. I tend to run decks with high land counts that can support Energy Flux. (Not saying this is good or bad... I just tend to run a lot of land and so I end up running this card.) Against most Shops decks, and again, Shops players are welcome to dispute this, landing Energy Flux is just game over. So it's not like you need a lot more. So the math on that would look like, every time I hit dredge with a hate card, it might improve my chances to win by 10% or so. Every time I hit Shops with a Flux, my chances to win go up dramatically, maybe by 40% or something. I shouldn't need to draw multiples of that card. Landing one should be plenty.

Another nice tactic, and my wife uses this to good effect, you are allowed to bring sideboard notes. My wife has a little book she carries with her to tourneys, with all her sideboard configurations against various decks. Example, if she see's an Oath deck, she looks it up for game 2 and makes an automatic board switch that she's already practiced and has written in her book.

Lastly, I really like cards that are good in multiple matchups. Cards like Containment Priest and Grafdigger's Cage are clearly awesome, because it hits Oath, Dredge, and anything running Tinker. Ingot Chewer is good against Shops type things, but has a splash effect against Dredge by clearing your opponent's Bridges. And so on.

It all depends on what the meta looks like and what decks you think you need extra help against given your initial matchup, and then how much help you think you need.

@Topical_Island I will definitely keep all this in mind, thank you very much.

The stronger the hate cards against non-blue decks, the more I think Vampiric Tutor and even Imperial Seal is correct.

I usually lump Aggro Shops (car shops) and eldrazi together for sideboarding purposes. So if i am going to lump stuff together it is usually for that matchup. Without knowing a lot about your deck i would say snuff out, snapcaster mage, bolt (to a lesser extent) the new fatal push, and maybe even something like shriekmaw or FTK could be reasonable since those both dodge reality smasher discard and thorn effects, but I don't know how that matches up with your mana bse.

In general point removal + snapcaster is where I want to be against large creature aggressive decks.

For mentor I think sulfur elemental is the best card, full stop if you have access to red. You need something that can handle both mentor and cleanup the tokens. I would still side in spot removal, but in my experience it isn't enough unless you have your own token generator. The white decks have been running some number of supreme verdict sometimes, for the same reason I think? Notion thief is also powerful in those matchups but only if you can protect the board too, i don't know if you are running young pyromancer or not.