It seems like if the balancer didn't put the pulleys in the correct location there would be issues with the normal V belts also. I haven't seen any complaints about that, so I'm sure the pulley position is same as stock, so the serpentine drive should work.
On the spacer, you mean the crank sleeve that goes behind the harmonic balancer, right? They are all the same length as far as I know; never seen one of a different length, even on a very early FE. There are aftermarket billet steel crank sleeves available from Robert Pond Motorsports if you can't find a stock one.