It just dawned on me that if manufacturers (distributors, retailers, ...) began reporting the RFOV for each of their eyepieces, in conjunction with the real focal length (to at least 1/10 mm), then we would immediately have the means whereby to compute the exact field stop diameter for the eyepiece, be it directly measurable, or only "effective" (due to the problem of the built in Barlow).

The precise field stop measurement for any eyepiece would be directly available from the equation:

FS = (RFOV * Eyepiece_FL)/57.296

The value of knowing the RFOV would simply be huge. No actual field stop measurement would ever again be required. Also there would be no need to ever again drift test for precise TFOV. In fact you could say that knowledge of an eyepieces RFOV would be "Majestic"!