zpool does not support the use of workername. Simply supply the BTC address you want to get paid in.
So, can I use just one BTC address for all (three) rigs?
.worker2
.worker3
etc....
I believe worker names are not supported; or rather; they arent to be attached to the login name as they do no good. I havent had any issues before adding one; but I know ive been told by crackfoo that they arent used.
Just point all your miners at the same username and all mined funds will be payed out to that account =)