Thanks Louey.
I guess I misread somewhere that a 1 1/4" took the same size hole as the 1". Of course I am now determined to use 1.25" pipe for my drains to get a little extra flow through my 120 AGA without it getting too noisy. I'll see if I can come up with a DIY design worthy of posting in here. the standard PVC fittings are just a little to narrow to get a confident seal. I will have to make a wider O-ring assembly to compensate for the lack of fail safe.