So from what I can work out with regard to dual carb options for single port heads are
1. Weber/empi 34 ict
2.empi 34 epc
3. Solex 34 ( CB performance)

Are there any others worth looking at ?

Which of the above option should I favor or just stay away from.

Is there much difference in performance between them.

I know I am asking alot I would like to get it right first go.
They are going on a 1500 bug running hide-a-way exshaust.
Thanks.

If you're after performance then the best option is to swap to twin-port heads and then put carbs on those! The conversion is not particularly expensive.

read here

http://www.aircooled.net/gnrlsite/resource/articles/carbs101.htm 

Any of the dual single barrels will work