Every time a Wurmcoil dies, you get two Wurms. If you Weld one of those Wurms (deathtouch) for Wurmcoil, now you have a Wurmcoil and a lifelink Wurm. Wash/rinse/repeat.
Sphinx is out of fashion, though. It was good against UR Delver, but it's actually pretty bad against Mentor Gush since they have StP and the ability to just grow it to 7/7.
So your plan is to simply make a bunch of 3/3 lifelink wurms to combat a 6/6 flying lifelinker with first strike and vigilance. It might work but I don't see it, seems slow to be honest.
It may be out of favor but I just like being prepared for it just in case. Blightsteel is alot easier to answer of course.