pstanz has a pryazole group.
fura has a furaza group.
this is the only difference chemically between the two. and the steroids act similarly in terms of gains.
fura is the stronger compound of the two.
fura stacked starting dosage will be about 300mg. and after you run it at 300mg, you'll want to see what it can do at 400-600 (600mg is the starting dosage i recomend if you run it solo)
pstanz when I ran it at 300mg e/d, didn't really add much of anything to my cycle. I'd say it will need to be ran in the 400-600mg range starting out stacked.
all in all, if you only have one bottle of each, i'd recomend running the hd solo, as a bottle of each wont add anything to your cycle, and will be a waste.
just save it until you can get a few more bottles, and make it count when you run it. you'll be glad you did.