What I was going for is if the buff is harder to find it should not be as fast to level as say doubler that has a lot of options and wont become a problem
Seeing as you can never compose a useful Global Booster, I don't think it matters how fast it levels.
Okay, okay, assuming you don't have enough Blue Slime Brews to last the year, you can supposedly make a useful GB as low as level 32 (220 + Distil 150 = 253). I still don't see it being in high demand. By the time many people reach composing level 32, BSB will come around again. They'll be better known and probably stockpiled in much greater numbers, like Zombie Brews were the second time around.
Meanwhile, to use a different point of comparison, AL doesn't go above 180 except for donation potions... and composing, where it maxes at 200 at level 11, before GB even starts. AL is also something most players will use much more frequently than GB. Conserve is similar, and that one could have a direct impact on the economy, which can't be said of GB.
Anyway, I voted for 100/10, although even 100/5 or 50/10 sounds fine. Looks like 50/10 would be more in line with other potions around that composing level.