1. if I que up 10 tanks and one spinner on a vehicle factory that is on infinite build, will I end up with 10x more tanks than spinners? 2. do metal extractors that have both a T1 and a T2 mex collect more metal than one that has only a T2?
Yes to both. With the mex let's say that t1 does 10 and t2 does 20. If you have both on a single metal point you would get 30 income.
Just to prevent confusion, T2 MEX generates 3.5 times more metal than a T1 MEX, not twice the amount.
when I colonize a new planet, I often forget that I have to build both t1 and t2 mex, I just build t2 and forget.