Claytons right. Ring AHPC, 0354436910, or email them for a tramp measurement form, measure the points as requested, fill out the form, include where you want eyelets for trapeze etc... send it off, pay for it, about $450 (bit less I think) it arrives ready to put on.

Mine was perfect fit, although I forgot the trapeze eyelets and I'm sending it back for them in the coming weeks.

Regards