I have encountered no issues with any of my eyepieces - Televue Pans and ES 68's, many different 82s, Pentax XLs and XWs, Morpheuses, and many others. Many perform a tad bit better due to the correction and field flattening the focal reducer provides. These days, I generally observe with an R/C almost all the time, and encounter zero issues with any 1.25" eyepiece.
Simple fact is that pretty much every good-quality 1.25" EP will play well with an R/C, as long as you remember that you are making your SCT a faster f/6.3 scope. Going from f/10 to f/6.3 will mean that edges will not be as sharp in less well-corrected eyepieces as in a more forgiving, slower f/10 system. This is why less expensive wide fields - Superviews, Hyperions, Luminoses, etc. - tend to soften at the edges in scopes that are faster than f/7.
That is - BIG IF HERE - you use the reducer with the recommended 1.25" diagonal and eyepieces for which it was designed.
Introduce a 2" diagonal and 2" eyepieces into the equation, and all bets are off. The added focal length of most 2" diagonals combined with an f/6.3 R/C makes it dicey. Most 2" diagonals (not all) are too long and exceed the proper corrector-to-eyepiece distance. This makes it impossible to bring some EPs to focus, and also effectively stops down the aperture of your scope. Essentially, by adding the 2" diagonal behind your R/C, you are moving your EP so far back that you run out of in-travel on your focuser to bring it to proper focus. You also cut off the edges of the light cone coming into your EP, effectively turning your 8" SCT into a 7" scope.
I (and many others) do successfully use 2" accessories with an R/C, but you need a diagonal with the shortest possible light path to reliably do so - often a 2" prism (expensive), an SCT nose piece that threads directly onto the R/C, or one with a shorter EP holder. I actually use negative profile 2" to 1.25" adapters that drop the EP farther down into my 2" diagonal to shorten the focal length even further.
There's a reason there are many threads here advising using either 2" alone, or 1.25" with an R/C, but not both to max out the field on your SCT.
Edited by PJBilotta, 08 April 2021 - 02:42 AM.