Plumbing in an external refugium

[hqgc]

Okay , final decision has been made. I can't fit a 'fuge in my sump so I am going to plumb in an external refugium. It is going to be a 10 gallon placed beside the main tank. I was planning to run 3/4 " pvc for pipe. Also I want to put the pump in the sump and then return it to the sump as well. Here are my questions:
1. Should I drill one or two holes in the ten gallon ( supply and return or just a bulkhead for the return?)
2.What size pump should I go for to supply my 'fuge ? From what I understand I am after low gph.
(F.Y.I. There is about two feet of "head" travel and four feet of horizontal travel.)
3. Will I need another heater in the 'fuge?
Thanx H.