Optimal number of stamps for a manila envelope?
I've been obsessing over how many stamps to put on a manila envelope for recommendations and such. Normally, when you mail manila envelopes, you get a specialized stamp from the post office based on weight. But as I need to give envelopes pre-stamped to my teachers/counselors/etc., I was wondering what the optimal number of 42 cent stamps is? Don't want to waste any, but don't want to get my envelopes resent to me by the US Mail!
Also, does anyone know if Princeton minds whether forms are sent in legal size envelopes or manila 9x12" envelopes? I know Stanford is pretty adamant about no folding...