Having "talked" (Emails) to DaveReb many times, the last suggestion is a good one. The Ti Bump is not as big as the Spec Bump. At about 4.5" closed, it's a good size. I also agree with previous posters in stating that since Dave wasn't happy (For one reason or another) with the small Seb, Alias I, or PT, then maybe it would be a good idea to get a different knife.
However, IIRC, the problem with the PT for Dave, was that he had problems getting it sharp. Maybe your sharpening skills are better & you ought to give a PT another try. I think the issues with the Seb & the Alias was their thumb-studs weren't comfortable, but maybe I'm wrong about that.
The Burke Rockstar sure looks nice, but man that is a wide knife. If you like Spydercos (& I believe you do), then maybe a Buck/Mayo TNT would be the way to go, since that has an oblong thumb-hole to open with. However, the Ti Bump is kind of similar to the Ti Cyclone, but is a little larger, hence probably more comfortable to handle.
Of course, I'm just giving my subjectiive opinion, which really doesn't mean much since I believe Dave already bought a small classic micarta Seb (Can't blame him, I have one myself) & sounds like he'll try to get the Rockstar later.