TI Flats only come in 43-100 I believe ...
I use 45-105 rounds but go to 45-100 for flats (Chromes).
For me (and everyone is different, so making string recommendations difficult), the transition of switching between 45-105 D'Addario Nickelwound and 45-100 Chromes is the most consistent in terms of tension.
Just previous to the Chromes (like two weeks ago), I had the TI flats. I could see why some would love them. I hated them ... and they cost $65 Canadian compared to the $35 Chromes. Multiply that by two actually since I have a Fender Jazz and a P-Bass and instead of being patient and just trying them on one bass, I restrung both at the same time.
I need some tension in the strings to be able to play the way I'm used to. The TIs are very low tension, lower than any rounds I've tried, and despite the tone, I was not playing the way I'm accustomed to and my technique was affected.
What strings are you currently using and do you like the tension of those?
I've burned through flats from RotoSounds (45-105), Fenders (45-95 and 50-100), TIs (43-100) and Chromes (50-105 and 45-100) all just in 2009, and the Chromes 45-100 are the only strings touching my basses from here on out.
If you do try those, just two bits of advice ... string them through the bridge even if stringing through the body is an option (they won't fit properly through the body and, quite frankly, I think all strings sound just as good and "set up" better through the bridge), and give them a good 10+ solid of playing time before you finalize judgement on them. Bright and clanky at first ... evens out very nicely in a short time and, from what I've heard from others, they'll stay that way forever.
