Paul - you should not be using tech wax in your process - it doesn't fit in well with the other products you are using. Your process should be:

Megs clay
AG SRP or Clearkote VMG
RMG
EXP
Natty's or Pinnacle.

If you're on a budget, then Natty's will be fine, don't worry about spending the extra on Pinnacle. I use Natty's on my own car. Don't worry about all the questions, me and Frayz don't mind at all Like you said - it's better to be certain before parting with your money!

Gareth