As far as taking gh pre-workout to burn fat, top competitor who used to train at my gym did something similar to this, but he didn't do any slin at all, just gh, he told me that he did 3ius am, then 3 pre and 4 pwo. Sometimes he would do 10 pre-workout, he said that what you will notice immediately is that you sweat like a M.F. and he did!
That's why I asked him what the deal was, I thought that he was on DNP or something, I've never taken DNP, but I heard that it makes you sweat like nothing else.
I've read that gh can cause some slight hypo reactions, if taken preworkout. On the other hand, I've also read that taking carbs with the gh is not advisable for some reason, if that's what you've been hearing I can see the logic between doing gh preworkout and saving the slin for PWO with carbs. I read it on some other board a while ago.
Personally since you are on this board, I would look into Datbtrues posts, if I was looking into doing anything with peptides, he really knows his stuff.