No they will not be on here as sources. Last year we had a guy selling powders(hometown powders) that started out legit then went flaky in a matter of 3-4 weeks, taking a few people to the cleaners if i'm not mistaken. Best thing you can do is get a few raw powder supplier names to start with, then do your homework and go from there. I am not endorsing anyone, but you might start looking with landmarkchem, redlionpharm, and qualityraws. Do some searched and see what you come up with. All seem to have good and bad reviews.
70% purity powder from chinese sources seems to be a common link with most of the powder resellers. I wish i could tell you how to avoid the 50% or below stuff, but it seems to be a problem occasionally for most of them. Also, if you are a 100 gram at a time guy i imagine your leverage is little to none. So, do your research and take a chance on the roulette wheel. Maybe brew 10 grams of your 100 and run a cycle, get bloods and decide what to do with the other 90 grams from there.
Wish i could help more but maybe guys with more experience will step up and give their tips.