Here are some measured inflated tire widths on Al33 rims, which we use in our RFSW3 wheels. The inner width of the rim is 19.6mm, which puts it in line with many of the current popular wider rims. There aren't a lot of surprises on this list, and with these data points it's possible to interpolate/extrapolate most of the other tires out there.
All tires inflated to 95psi prior to measurement. Format is tire make & model / size / inflated width:
Continental GP4000sII / 23 / 25.65
Continental GP4000sII / 25 / 28.60
Specialized S-Works Turbo / 24 / 25.40
Specialized S-Works Turbo / 26 / 27.15
Maxxis Padrone TL / 25 / 26.50
Michelin Pro4 SC / 23 / 24.5
Again, no huge surprises. Every tire is somewhat bigger than stated size, and GP4000s considerably so. With an outside brake track width of 25 and an overal widest width of 26.2, the rims themselves shouldn't cause fit issues with any frames we know of.
We have helped to arrange a wind tunnel test for Al33 and a bunch of other comparably relevant wheels on 2/9. We will post the information from that as soon thereafter as possible. I can assure you that we're as curious about that as you are.
Following that test, we'll make the order pages live.