[Leica] Prescription lens for eyepieces

["Julian Koplen" <jkoplen@mindspring.com>]

I would appreciate information about how to obtain prescription eyepieces
for M6 and R4.  My correction exceeds what is available "off the shelf".  My
distance diopter correction is +4 and near is "add 2.5".  I understand that
all I have to do is inform the optical lab that Leica puts -0.5 in the M
eyepiece and -1.0 in the R.

Does that make sense, and does anyone know of labs that can fashion the
proper shape and size lenses that are required.

A related question, if anyone has direct experience, is whether it is worth
getting the rotating eyepiece for astigmatism correction, or is that feature
more trouble than it is worth?

Thanks for any help............Julian

P.S. Forgive if multiple messages appear.  I may have had message format
problems.