Yes, TI Flats on my '68. I put a set of La Bella Deep Talkin' Bass flats on my GSR M85II on Hieronymous's recommendation, and I've been very pleased with them so far. Might be a good option for the Starfire II at a more reasonable price, and they're a bit stiffer than the TI Flats if that appeals to you. I haven't tried that combo yet on the SFII, though.
Yes. I don't obsess over strings but I think I have TI flats on one Starfire and D'addario flats on the other. I can tell a difference in feel but not enough to justify the cost differential. Of course, I am the guy who kept a set of RotoSounds on the -67 Starfire for 30+ years and now has them on the JS II
DR Legend flatwounds are my favorites so far for my 1970 Starfire (my main player) which are the "short scale" set. Length-wise they fit pretty well, though sometimes you you have to trim the silk windings back just a tad to clear the nut. Only takes an extra minute or two with a razor. I can't recall every set I've tried on this bass, but definitely Fender flats, GHS brite flats, Rotosound, D'Addario Chromes, and Thomastik Infelds.
My 1967 Starfire has LaBella black nylon tapewounds on it, "medium scale" set fits perfectly as others have mentioned. For some reason this Starfire likes lower tension strings more... it does have a noticeably slimmer neck and thinner fretwire, so that might have something to do with it. Thomastik Infeld flatwounds were pretty nice on this one though they had the same issues that I have encountered with every TI bass flatwound set that I've tried, which is a noticeably thinner/weaker sounding E string and the fact that they never seem to feel equally smooth from string to string. I can't really explain it, as I love both their electric guitar and classical guitar flatwound offerings and have never had similar issues with those sets.
Rather than editing my previous post, I thought I should add that I've probably tried just about every type of flatwound string available on the market over the last 10-15 years, but I've found that different basses definitely like different types/makes of strings more than others and I haven't tried them all on any one bass. Also, formulas for strings change over the years, most notably in relatively recent years, Fender flatwounds come to mind. Finally there's the age factor, as different strings take different amounts of time to "break in" and/or "deaden". I've had sets that I liked for a while that then became too thuddy and lifeless. I've had others that were unpleasantly bright, clanky, and zingy out of the package but broke in beautifully over the course of a few weeks or months... So there are a lot of variables to take into account when it comes to string choice.
Mellow One, did you ever try the Hofner set sold by TI? Not as easy to find, but I came to prefer them. The only difference from the stock set is that the E is a 96 or something. A little thinner up at the nut.
The reason I seek them out is that the thinner E string seems to match the overall feel across the strings. For some reason I prefer that. Tactile rather than sonic.
Mr. Happy, I have not tried the Hofner TI set. For the most part, I like heavier gauge strings, so seeing a gauge 96 E would typically make me run the other way. But if it has the same smooth/polished feel that the D and G always seem to have, that could be a game changer, at least within the realm of TI's. That would still leave the A string feeling not-as-smooth/polished though... at least on the sets that I"ve come across.
Pyramids I only tried once I think and it's been so long that I don't remember much about them. Should probably pick up a set again at some point to try on my #1.
By the way (VEER ALERT!), the roundwound TI strings that were on the ol' Polish bass are now on my Kay jumbo guitar that I converted into an acoustic bass recently. They are fantastic in that context! Nice mid-presence, loud, and warm sounding, unlike phosphor bronze strings I've tried. Flats sounded nice on this one, but they were too quiet to really compete with a dreadnought 6-strings.
They are hands-down my favorite roundwounds I've ever tried. If I owned an Alembic or a Thunderbird bass (the only two I can think of that I would love to have in my stable but prefer rounds on), those would likely be the first type I'd string them up with.