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Just to remind facts that are now forgotten. Some old eyepieces formula, I would say before modern addition of the Smyth/Barlow front group, were designed to fit with the complete scope optic formula, and sometimes not conceived for astronomy.
Best example is the Abbe Ortho, when you check an afocal mode design on f10/f15 doublet refractor, nothing is better with 4 lenses and 4 air-glass surfaces. Do you think it was at first for astronomy ? Second example in my mind : Erfle 2 ... designed for short fl binocular.
König assymetrical plössl (Clave / Brandon) fit best the König B apo triplet or newton reflector.
There are other tuning that have been made, trying to keep minimal lens count (calculation were hard at those time, and AR treatment were not performing as good as now) : 2+1 könig has two or more versions, one is astigmatic, other is acomatic.
Late evolution, that needed good AR treatment, and were microscopy/planetary tuned, have been made with 5-6 lens (Astroplan, BerteleWA/Scidmore...)
I don't know more complicated consistent group. Lastest evolutions are made with addition of front Smyth/Barlow and intermediate flattening field group. --------------------------------------
About practical EP and for short fl, I like much TV Radian (partial retro engineered) and TMB planetary designs (air-spaced Smyth/Barlow and simple könig 2+1) Better made TMB, with enhanced AR treatment, high quality glass (like the v1) would be ultimate long ER (comfortable) planetary. Maybe TV Delite, that I don't know, fits that. I won't give any preference about "old" design because I did not tested deeply them. One important thing is to say on which telescope you made the check.
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