CORRECTION
I was wrong with the seal dimensions above.
The correct seal dimensions are:
ID: 30 mm
HT: 10 mm
OD: 52-53 mm
On the OD, the best seal probably depends on the state of your tub's bore. The best bet always is measuring the bore with a caliper once the old seal is removed. Also, if the bore is in bad shape, you could hack it by getting a repair sleeve #99205 for the bore and go for the 52mm seal.
FYI, generic seals are usually for oil/grease. I read a post here that the angles of the lips differ for water/steam/aqueous fluids and oil/grease seals, but I'm not sure how crucial this is for such a low-duty application like washers.
Modern Viton/FKM seals last way longer than the original rubber/neoprene/nitrile ones. Moreover, Viton type GF is specifically superior for water/steam/aqueous fluids so they should be a superior option, right?
Also, seals of other heights should work too if they don't stick out over the tub's bore edge. That said, does anyone have an opinion on using multiple seals (eg., two 5mm-thick ones instead of a single 10mm)? And how about using double-spring seals rather than single-spring? I ask b/c the contact surface on the shaft in my machine is 20mm wide and there is enough room to spare in the bore between the inner bearing and the seal.
Cheers,
Fernan