Charlemagne
Black Belt
Next I think it is clear the principles meet well since others who study WC under other Lineages PLUS PTK (not Inosanto Kali) concur there is a good mesh means... It is a good mesh. Sometimes, things just fit.
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As I noted above, I study PTK and I don't think it is a good mesh with WC. Of the arts the OP listed, it was the best option. However, the strategy of the two systems are so different that I actually think it would be problematic in the long run. In PTK, our empty hands comes from the knife. In some FMA's this is said, but not really done. In PTK, this is really how it works. If you look at a place where PTK is being trained classically and not mixed with other stuff, you can look at any empty hand movement and find the same movement in solo or double daga.
Because of this, I believe that WC would end up conflicting with PTK in the long haul. WC wants to dominate centerline. PTK only goes to center line in specific instances, particularly in espada y daga/two long weapons or, when you have managed to quarter your opponent and have either their flank or have gotten then moving in a direction that you want them to, and have the proper timing. I suppose another time might be due to environmental consderations (not getting pushed into a corner, etc.). The bottom line is that the overall strategy of WC and PTK differs greatly due to the reasons for the systems' existence and their assumptions about fighting.
If one is looking to beef up the mano y mano aspect of things and train PTK, my strong suggestion would be Thai Boxing instead of WC. Thai Boxing would allow more easily borrowing some techniques to blend in with the core strategy of PTK (with the exception of throwing punches). In addition the mechanics of elbows and kicks in MT and PTK are not too different . Knees can be different (PTK tends to throw the knees more forward versus up as in MT), but that is more of a function of the intent of the knee than anything else, and there are times when PTK throws a rising knee as well. Straight line punches can easily be open hand strikes with the palm, which PTK has already, and then maintain the strategy of PTK of not taking the chance of damaging your hand to the point that you cannot grasp your weapon.