OP
I'll be looking at ordering one with the system installed, so I'll definitely give the 4" pipe try!Do you already have a suit or will you be ordering one with the system installed on it? In a pinch you can get a 4 in ID pipe and that will be close @ 101mm. Cut it to a 1 in ring and give it a shot. Give your LDS and those a bit further away a call and see if they have one.
Honestly never even occurred to me to make a run to Home Depot for a quick try on sizing.... For sure still going to make some calls around tomorrow and see what I can find in the extended area though