What are your future plans/goals? My advice would be to go somewhat overkill on the lines. It gets pricey replacing lines and fittings 2 years from now when you build a new motor or decide to add a little spray. Ask me how I know .....I would go with -8 minimum from the tank to pump and from pump to regulator (skip the mechanical pump), and -6 from regulator to carb. Just my

Randy