I explored the TIs with a different B string, but the tone of the TIs is so distinctive that I couldn't find anything for a B that was remotely passable alongside them. Right now I use an unmatched set; a Payson GW B with La Bella E-G. This is, by a pretty good margin, the best solution I've found for flats on a Combustion. There is a tonal change between the two string types, but no one notices it unless I tell them or they look at the windings on the headstock (which no one has ever mentioned to me - people are too busy looking at the crooked frets).
The TIs sound and feel so good, though, that I might look at this idea of modifying the saddle for the B....
Or, if Sheldon just makes those flats, I think my problems will be solved....