Will this rigid foam insulation board work well?

[DrGribble]

If you go this way I want to see the job in action! I really REALLY wanted to go with this myself but simply couldn't justify it in the budget.

Yeah I would LOVE to use this stuff too but I can't afford the costs either, maybe someday I'll rebuild and have a real budget I'm sort of winging it as I go for now but I find it to be fun experimenting anyway.