They shared some of their database with me and I can't get it to load here, but here are the narrowed down choices.
Part# ID OD Thickness
33-1001 26mm 47mm 3.5mm (This one seems the least desirable.)
33-1023 26.5mm 52mm 3.5mm (This one will have the OD riding on the orange part of the bracket by .5mm, or on the seam between the bracket and race which might tear the seal up if the bracket's not smooth. Either way, it will ensure the bare steel of the race is always covered. I don't like the ID, tho'...might not sit concentrically.)
33-1024 26mm 48mm 5mm (This one's kinda tall. If the nut doesn't sit completely in the race, it might be a consideration.)
33-1025 25mm 47mm 3mm (I'm gamblin' on this to be the one...low and concentrically tight.)
Given the prices, I think they're all $1.80, I might just buy a 1023 and 1024, also, now that I think about it.
Stuff to think about and, if you have the access to the shaft, something to measure...
The outer race of the bracket's bearing has an ID of 42mm and an OD of 51mm.
The nut's thread ID is 20.4mm. Take into account the threads on the shaft will likely add ~1.5mm and we're at 22mm.
How big does the shaft get before stepping up to the splines? This is where the seal will sit. I'm guessin' around 24mm.
The heim seal provided by RSP was prolly a leftover from previous versions where, from internet pics, it looks like the nut sat higher than the bearing housing. I can totally see using the heim seal in those applications.