Dont waste your money on a diff. drop to begin with, they do very little if anything to alleviate driveshaft angle. And yes, the budbuilt skid will clear a diff. drop, but Id still ditch the diff. drop and lower the front end down to 2.5" of lift and you should be good.
It seems 3/16" is the only thickness that Tacoma skidplates come in some. The only problem I see with some of these skidplates is if you lift your vehicle to the point were you need diff drop kit you are S.O.L. If that is the case it makes my suspension choice very very easy.