Thank you Gentlemen. Lee valley gauge ordered. Looking for a flat floored friend.
If you have a reasonable floor to start on you can create a flat patch using a spirit level and some shims of plywood, or even magazines (I think you guys use 'masonite' for these things) Side to side level is more important than front to rear. To set up tracking/toe the best and most tried and tested method in the motorsport world is to set up parallel string lines (bright fishing line is best) at wheel centre height, you can then take all your measurements
If I'm doing a particular car regularly I make a set up that clamps to the car in some convenient and repeatable way, this makes it easier to jack up to make adjustments and also to roll / jounce the car to settle it without the need to keep re-setting your string lines.
Apologies if I'm repeating stuff that's already posted somewhere, but people get very afraid of geo set ups like its a black art, it's not, if you've built a car you can certainly set it up and it's very satisfying!