Question

How does crystal size compare in extrusive vs.intrusive rock

Answer 1

I would say that intrusive means the solidification of the material inside the volcano and extrusive is the solidification outside the volcano or in the surface of the crust.
Inside the volcano, temperatures are higher than outside it.
Meaning the higher the temperature, the higher the dilation. That is to say that intrusive rocks shall be bigger than extrusive ones.