For the 6P incandescent vs. TK11 comparison in terms of color rendition, output and throw, generic808 seems to be spot on. The incandescent will have better color rendition (particularly for eyes that are accustomed to sunlight), but the TK11 will have significantly better throw and output than the stock 6P (i.e., with P60 lamp assembly).
If color rendition is your top priority, then there shouldn't be anything holding you back from getting the 6P. Then, for output, the P61 will give you (I think) pretty close to the same perceived brightness as the TK11. The TK11 probably technically puts out more lumens than the P61 lamp, but I'd doubt your eye would detect much of a difference. My eye can't see much of one between my P61 and my Malkoff M60.
Throw, however, is an interesting thing. With the P61, you have a lot of light to put out the front of the lamp, which means you need more filament to burn. But more filament means a bigger area/volume of a light source. As such, it won't focus as perfectly as the smaller filament of the P60 lamp. The net result of this is that the P61 gives you a wide, very bright hotspot that throws a decent amount, whereas the P60 throws a bit further, but is dimmer. At "extreme" distances I've found the P60 to light things up better than the P61, but at those distances you're better off with a light with a huge/deep reflector (e.g., C or D Mag, DBS, Tiablo A9). As for a comparison in throw between the P60/P61 and the TK11, I couldn't say, as I haven't handled the TK11. I'd expect it to throw noticeably farther than the P60/P61, but probably not by enough to put it in the same class as the DBS et al.
In the end, I'd probably consider the color rendition and runtime to be the primary deciding factors. If you really need/want the color rendition, and are fine with (a lot) less runtime, go with the P60/P61. If runtime is pretty important too, or even more important, then you may want to stick with the TK11.
Also, as generic808 suggested, the 9P and/or KT1/KT2 turbohead are also options to consider. From what I've heard, the P91 lamp option for the 9P will be significantly brighter than the TK11 (haven't heard much about it's throw, though). The turbohead will give you very competitive throw, but at a much higher cost.
In your place, I'd probably get the 9P, and P91 lamp, so as to at least have the option of super output.