For butts and briskets
I figger weight 40% lose in smokeing process
and i figger poundage needed at 1/3# per person (man,woman or child)
so if you start will 100# uncooked meat, you will get aprox 60# of meat, that give you 180 sammies. this is what i use and come out fine.
If there is beer/party/dance, you may up the poundage needed, people will come back for more as the nite progress's