micros take waay long to build. if you buy the micro, you're not gonna be riding it for at least a month or two.
i bought mine about 2 & 1/2 months ago, and i just finished it recently.
im pretty sure if you use a pro headtube in an XT deck (not that they fit) it would be waaay past 90 degrees. you be riding an obtuse angle, which would not work.