I put a set of the RS77M's on my new Guild Starfire I bass last night. Personally, I find them to be neither "floppy" (something I don't like at all), nor particularly high tension. The posted tension for these strings is 137.31 lbs., which IME is more or less average for lighter gauge, medium scale flats. They seem very nice, so far; they feel good; fairly supple, but I can play them with a pick - with no technique adjustment - which is a big plus in my book. So... if you have them on an Epiphone Viola Bass? I can't imagine they'd be much different than the ones on my Guild. But, yes; heavier gauge La Bellas are going to be stiffer - and higher tension - than the Rotos. I have La Bella medium scale 760FL's (43-104) on one of my violin basses; the difference in stiffness; perceived tension; and feel is... not drastic; but, it is rather noticeable. I'd have no problem with the Roto's on any of my other basses with trapeze tailpieces and separate bridges - floating or otherwise. And, I have several of them. But, I suppose it all boils down to what you like. And, with basses like these? Finding strings that will actually tune up - and also, at least more or less intonate - IME can sometimes be hard to do. When I do? I'm very reluctant to try different strings on that bass, after that. But, if
you want to experiment? With very few exceptions - like short scale Pyramids and TI Jazz Flats/Jazz Rounds - you're going to need medium scale strings. Some short scale GHS strings
might fit, but, I couldn't swear to it. Much as I like my basses like these? They can be kind of a pain, sometimes...