Hi 4strokeIt's a good question. Here in NZ, trials isn't as popular as in the UK so the restrictions on bikes is not so severe. As long as you have an aircooled bike you can ride. We have late aircooled GasGasers through to TL's and even some old british bikes competing against each other.
The other reason for wanting to do this is that bike building is fun
Regarding your offer of measurements etc, yes please especially the front mount for the shock. Also some good photos be be really appreciated.
I'll pm you a drawing if you don't mind and perhaps you could fill in the measurements for me?
Thanks