do you have the o-ring custom made?
For this one, I will make my own custom o-ring using EPDM cord stock, rated for water and steam, from McMaster Carr
http://www.mcmaster.com/#o-rings/=wk3gm4Just cut it to length and super glue the end together using the recommended Loctite Instant Adhesive
http://www.mcmaster.com/#7569a22/=wk3j9uThis groove ended up having a circumference of 35.887" which equates to an o-ring diameter 11.423" at its centerline. Had McMaster Carr stocked a 1/16" nominal, .070 actual diameter, o-ring that was close enough to that size, I could have manipulated the contour in Solid Works to match exactly.
If I had a low-profile intake, there would be more material to work with and I could have stepped up the cross-section diameter to 1/8" nominal, .139 actual diameter. McMaster Carr normally stocks 11-1/2" o-rings that have a diameter of 11.623 at the centerline. However, both the Berkeley suction housing and intake have thin flanges and I feel removing an extra .053 - .057 would reduce the thickness too much and develop cracks. It was exactly this reason why I chose to o-ring the intake rather than the suction housing.