The recipe for nips or firecrackers calls for one gram. I tried nips with .5 gram, and I got high, but it felt like it needed one.more.cracker! Go with at least a gram.

n.i.p.s - nutella infused pot snax
materials needed: four crackers, nutella (a chocolate spread used on toast etc), at least a gram of bud.
directions: throw weed in coffee grinder until powdered. spread nutella on one side of each of four crackers. spread half a gram on two crackers, and sandwich them together. repeat. toss in oven for at least fifteen minutes.

p.s. You can substitute the nutella for peanut butter to make firecrackers. In response to your question, I'd go with at least a gram, but you can go with two if you're not sure. Shwag is best for this purpose.. I need to pick some up.