Hi Marc
I have a Vixen eyepiece projection unit that is very well made and machined but it will only accept slim 1 ¼ eyepieces.
My Vixen 10mm Plossl will comfortably fit but my Takahashi LE 5mm eyepiece will not fit. My 10mm Radian, 24mm Panoptic and 14mm XW have a snowflake in hells chance of fitting.
Cheers
Dennis