I perhaps would have thought a single 45, particularly with those cam specs you put up earlier (that is the cam you are running?).
Smallest venturis you can get I think are 28mm, and they WILL be too small for your motor. my 3K has twins, and i run 32mm chokes, and the 2t-G has twins with 34's (I think). However, smaller venturi's will keep the fuel bill down.
True, Dellorto parts are about twice the price of Weber parts.