I haven't done any work on this because I'm stuck looking for a suitable vacuum pump that doesn't cost an arm and a leg. 

The vacuum level isn't that high, but most chinesium-grade  pumps I've seen don't look that promising.

  I may have found one that fits the bill, both in price and performance. It's a  second hand, 2 stage pump. Hope it also works. Sometime next week I'll find out if this is really the case or I just threw away 50 Euros.

I've also been thinking about the set-up and  fittings I'm going to use. I basically want a set-up that's easy to disassemble and also holds a vacuum. Kind of much for them, but I'll test this out once I have  the pump (if it works)