Radians: performance variations

Years ago I had several Radians that I sold in favor of other eyepieces. Many of the folks here seem to favor them, so I was thinking of revisiting them. For use in an 8" f/6 dob I've been looking at the 12mm and the 4mm. Problem is, I've heard some folks say that some focal lengths perform better than others, for example,that the 5mm and 3mm outperform the 4mm. I believe they are scaled designs. Do any of the folks have experience with this? Thanks for any insights you maybe able to offer!
Larry

I have the 3-4-5-6mm Radians and I have found no differences in their performance really.
Many complaints I read have to do with lateral color, which I find to be the same as a TMB/BO in my testing. The color is at the very edge and exactly like that of the TMB/BO.
For me, not a problem at all, I am looking for on axis performance with an EP of that power.

Bill:
Interesting! Maybe if we could get Al to make a 40* Nagler....

Well, if I may submit that there're probably more variations amongst eyeballs than there are in the Radians ;-). Afterall, my pairs never got the QC they should have deserved ;-). Also, most people (including me) seem to be able to match one or more pair just fine for binoviewing.

Regarding the reflection, yes this can happen. I think someone determined long time ago that light can reflect from the cornea and onto the concave lens of the Radian. This can easily be verified by the movement of the reflection.

Ron B[ee]