I can't say I ever owned one, but a friend owned a 13.1 Coulter and I looked thru it frequently. You're description above is pretty spot on. He ended up trashing everything but the primary, refiguring it and rebuilding the entire scope to his liking. This was the mid nineties. At the same time, I owned a 10" Meade Starfinder and that didn't perform much better. I feel I needed to make endless mods just to get it to perform adequately.