Looks like they're all 1/8". I just added up all the lengths from the parts page and it cam to 8.8ft, so maybe 15ft to allow for error. They're all 3mm id x 6mm od. Your going to have to premix some fuel to idle in the water on until the lines get purged. Normally I like to prefill oil lines with a 50cc syringe after I get them positioned, plug one end with finger, remove syringe, and attach it to pump. Still might get a air bubble or two, but it's better piece of mind for the few minutes of idling while purging. Couldn't hurt to bleed the pump for a min after attaching the lines to make sure no air got in there somehow also.
Again, don't get the lines mixed up. They don't all have the same flow rate.