Hi Doug,
The shortest pair I have used and liked is the 12mm Agena Astro WA pair.
I prefer longer ER for binoviewing so I use 18mm orthos as my shortest pair with the 1.6 OCS and TV 2X and 3X barlows, easier to change a barlow than eyepieces ....the 3X was yours.... thanks so much
GSO superview 20mm's from what I have read are OK but I haven't used them, though I did have the 15's and they were really good. 20mm ES 68 vignettes a tiny bit, 19mm Flat Fields of all types are supposed to be good, without vignetting, but I haven't used them.
Matt