I'm inbetween a tech and an EE... my job title is Engineeering Tech, and that Shavano site has been a point of reference for years... I guess you can say I'm geek of sorts
You know what's weird, that first thread I sent you from the boogie board, the poster is a friend of mine, so is the guitar player, Taylor Harvey. I have 3 of the THB cds

I just noticed when I went back to the thread.... small world!!
Anyway, as far as crossovers go, I've never messed around with them much. The concept is simple enough. As far as your cab is concerned, if you're going to try to get it back to it's original setup, a schematic of that particular crossover would be really beneficial. When you said everything was "blown", do you mean it was fried? Can you tell if it looked anything like this

The capacitor I have is non-polarized, it looks like the ones in the pic above.