What would be a must tool or widgit...for kit building?
Im waiting on my first Airsail Kit and want to be prepared.[]
What sort of material should I use to to pin the parts down on..Im building in a small bedroom so not lots of room.

A hollow core door is a great building board. It's nice and flat. Perhaps you can slide it under your bed when you're not building. Acoustic ceiling tiles make a good top for pinning, although now I am using a Magic Magnetic building board system that works great. I attached it to the door I use with double sided tape.

A Dremel Tool! Is an absolute must!

This little tool will cut, drill, sand and polish (I sound like an advertisement) and it is all in a hand held tool that is very inexpensive.

Once you use one you'll wonder how you ever built before.

Here in the UK we have a thing called plasterboard, which is used in building house etc. I guess you have this in the US.

A 1800mmx900mmx9.5mm sheet cost £2.59, it's as flat as you can get, you can cut it to suit (edge it with masking tape) and it takes pins.