I currently use tap plastics, i don't use their platinum as at this point it's a little to costly for me. I use their normal casting silicone says it takes 8 hours to set, i typically let it sit under pressure for around 24-30 hours to ensure it sets completely. I have had stuff not set in 20 hours before and wasted the silicone, but it was winter and around 40-50 degrees out, and i cast in a garage that is not heated so i think the cold increases the time to set.
http://www.tapplastics.com/I currently use their casting resin also, the work time is perhaps 2 minutes, i can fill 3-4 molds 28mm trooper sized with extras in each trooper casting. The detail is fantastic, i recommend using a mold release as this resin saps the silicone of it's oils very badly, but has a very good mould life if used with mold release agent.
For the dye i just use alumilite dyes which are cheap and can be found at hobby lobby, i was very excited to find this out actually, they carry a lot of casting stuff i had only ever seen at a specialty store. They regularly have 40% off one item coupons which can help the purchase of higher priced items.
If you have any other questions about any of the stuff i said i'm more then happy to help.
Blind-