I dont see why it would hurt. non peg mgf is in and out of the blood so fast if it were an issue it would be over fast.
I really dont see it being an issue anyway though.
My monkey has been running peg-mgf daily along with pre and post workout slin and has had no issues.
He runs IGF1LR3 until that bottle is gone then PEG MGF until that bottle is gone back and forth.
Tried doing the Pre workout IGF and post work out MGF thing a few times and it really seemed to be more of a pain than it might have been worth. In other words no benefits were seen doing it that way.
However running one bottle then the other consecutively is cheaper and seems to actually be improved from the other method.
Persoanly I think your subject will get better use of the slin PRE workout then MGF after the work out with a touch more slin.
Pre workout slin has worked fantastic for my monkey.
Pre and post is best but the shot post should be minimal until your test subject gets used to it