I don't have the EP with me - its out in the shed and its too cold to go out there at the moment!
But it is for a FOV of 66 degrees and from memory the ER is at least 20mm, probably to do with the wide FOV in a 1.25" EP. Its the first time that I have used an EP with this type of ER.
Judging by your comments it seems that difficulty in keeping eyes in the right place is all part of the larger ER factor.
And am I to take it that there is no way of making the viewing more comfortable?
Cheers!
Popeye