I'm not an expert on these, but I did some research on using these lenses on 8x10 as I may buy a 355 G-Claron. All are process lenses. The G-Claron is a 6-element plasmat and has a lot of coverage for it's size, so lots of movement for a G-Claron on 8x10. A WA G-Claron is reported by some as an enlarger lens used on shorter column vertical enlargers. Some have reported that WA G-Clarons are soft at infinity.
A Repro Claron is a 4-element dialyte like an Artar, with much less coverage. A rule of thumb for the dialytes is that the focal length you need to be useful is about the same as the required format diagonal. So about 310mm diagonal for 8x10 vs 305 for the focal length. So you should be able to use a 305 Repro Claron on an 8x10 but you will not have nearly as much movement as with the plasmat G-Claron.
I use a 305 Repo Claron on 4X5. When I spoke with Schneider before purchasing the lens they said that the performance should be comparable to the G Claron provided both lenses were stopped down below F22. They did say that the lens did not have as much coverage as the G Claron. I have never mounted my lens on a Deardorff board to try it's coverage on 8X10. I have always felt that it would not cover. Perhaps I should try it.
As Steve stated, the Repro-Claron is a dialyte type lens. Schneider listed this lens as covering 46 degrees, which is much less than the 64 degrees of the G-Claron. With 46 degrees coverage, the Repro-Claron focused on infinity will cover a circle with a diameter of 260 mm. Obviously, this isn't enough for 8x10. It would work for 8x10 as a macro lens, from 1:5 to higher magnifications.
"Claron" was Schneider's brand name for any lens intended for copying. This covered a range of needs and thus of lens designs. Merely having "Claron" in the name implies no similarity to the popular G-Claron other than the lens is likely well corrected for the reproduction ratios useful for some sort of copy work.
P.S. I am interested in the Repro-Clarons as part of my study of radioactive lenses. The Repro-Clarons include glass containing thorium and are thus mildly radioactive. They typically will have a slight yellow cast from self-induced radiation damage of the thorium glass.
I own and use all 3. WA G-Claron's are a huge double gauss 4 element 4 group lens. Trouble is they're giant and don't really cover any more than the tiny G-Claron will in the same length. G-Clarons are listed at 64 degrees but when stopped down past f22 they actually cover about 82 degrees. You can use a 305 G-Claron on an 11X14 camera and it would have lots of movement on an 8X10. Repro Claron's are dialyt. 4 element 4 group and to answer your question, a 305 has a circle of illumination far past it's useable "coverage" circle. Schneider didn't put a mechanical vignette in. So on an 8X10 you'll see an image on your 8X10 screen but when you get out to the edge it falls off super quick into mush. I don't consider my 305 Repro Claron useful for 8X10 even though it covers. A 355 Repro and even better, a 420 Repro-Claron are fine 8X10 choices. For 305 though, look for a G-Claron. Avoid the WA G-Clarons.
I have a 305 and a 210 G-Claron. They both do 8x10 pretty easily. The 210 ;does need to be stopped down past f 22 to get the corners covered but it is a passable wide lens for 8x10. The 305 as mentioned above covers 11x14 and handles 8x10 easily. I like both. They are not multi coated but are single coated lenses. Both the 305 and the 210 screw directly into a Copal #1 shutter without any spacing issues.