Phew!! *wipes forehead* Just got through this whole thread! Got kind of derailed there huh?
To the OP, I third, fourth, massively endorse a marti - LOVE 'em!! Sure, some do use them as a "milder" form of correction if that's how you want to train, but many people use them because they're simply more comfortable for the dog. I find with my guys they can sit looser on the neck, move about easier, and STILL won't slip off if you have a pencil-head ducking his head for a sniff. Limited slips are nice too, but I'm a total marti fan.
As for the reactivity, have you tried teaching some default behaviors? Like maybe a default attention? There are some fantastic exercises in McDevitt's "Control Unleashed" that work really well with reactive dogs too (its not just for performance dogs). Might want to check it out