I found that Sumatra beans benefit from longer off gassing times with 3 days being the best tasting for my cup. Earlier than that was subpar.
As for grinding only what you need - these guys nailed it.
As for roast profiles, try smaller batches at different finishing points. I likes my Sumatra at FC drifting to FC+. Africans generally tasted great in the C to C+ range and Central Americans C+ to FC. Your tastes will vary.