I payed the 5191 a while back, when shopping for gretsch's that had what i hoped would be thinner necks. At the time i was playing a 5129 and a 6122 1962. I though both of them had a chunky neck, at least according to how my hands felt them. The 5191 played very easily to. I would compare it closer to the way my strat played compared to the other gretsch's. With the exception of my hotrod, which I got due to the thinner neck, the 5191 was the most comfortable gretsch.
Filtertron Gretsch's and Les paul fill in the model, are as you say apples and oranges. I don't think you will get the same sound, regardless of pickup choice. If you play really loud, even with the bracing in the 5191, you will run into feedback eventually. How ever, if you are considering a new 5191, which is not a bad guitar, for a little bit more ypou can get a used pro series Jet. It has, what i believe, the best of both worlds for what you are looking to get. Take a look at them, and I think if you played one, you might appreciate it.
Good luck, and welcome to the forum.
Never pet a dog that is foaming at the mouth.