Snoopy1
640cc Uber Pimp
It will keep some of the weight ahead of the tube which "should" help with balance.
From your original post I thought you were worried about installing the tank behind the CG, two equal sized tanks mounted on each side of the CG solves this problem.
As far as sucking fuel there will not be any problem with the Walbro style carburetor. I have read a Walbro can suck gas vertically 3 feet however I have never tried this myself. This came from a reliable source
Thanks guys splitting the tanks makes sense did not think of that way will look into the setup and see how it all fits, thanks.