I can plug all your stuff into my calculator, but I need to know basically everything you can tell me about your setup. I've got your bow weight, draw length, and poundage. Need the weight of stuff on the strings (peep, silencers, d-loop, etc. If you don't know, just guess 20 grains), point weight, if you're using wraps or not, if so the weight of those, then which arrows, inserts, and nocks you're using.
Just guessing at a standard point weight of 100gr, insert weight of around 15gr, nock of around 9gr, and 3 blazers with no wraps, 20 grains on your strings, and a 28" arrow, you'd need to be around .430 for spine. Which you shouldn't have any trouble hitting with a TON of arrows on the market.