RE: Welcome to Club SAITO !
Gavin,
I have the CG Ultimate with a 1.20 mounted horizontal. If you plan the same mounting for your 1.25, there is not too many options for a pitts installation. You will probably have to go with another solution. You could consider the Saito 90 adapter with the stock muffler or other options to bring the exhaust out the bottom of the cowl.
Jim