3/8" minimum mandatory. You can't have too big of a fuel line, only too small.
As for a fuel pump, the Carter electric pumps (if they've not changed the design) are one piece, submersing the rotor in fuel. The only seal that can possibly leak is the main seal (crimped) which holds the pump halves together. Really a neat design, as it keeps the pump motor cool.
While the Carter pumps are not rated for Meth, I have run meth with them for years prior to moving to mechanical injection.
http://store.summitracing.com/partde...5&autoview=sku