Guys

Yes, kit comes with a 6-6mm Festo joiner if you go two tanks. Bob with a P70 won't need the second tank unless he wants to use it for smoke...

An air leak there would not matter as far as running goes.
I'm going to change my 6-6 joiner for a 6-6 ball valve which allows the main tank to be sealed with the wing off.

Wing is too small (thin) for any std tank to fit.

Ron I will do shots-but the model is at home and I am off to a show tonight so it will be Monday now.

Regards

Dave