Hmm...I responded to this yesterday, but it's not here, and that's not the 1st time that's happened. This wait-for-the-full-time-babysitter-and-sometimes-your-stuff-doesn't-show policy of A-goN is highly annoying.
1. I'd replace your stranded jumpers with SHORT pieces of solid 14g. copper household wiring.
2. One certainly can adjust the frequency balance using tools, but we all still end up tweaking it by ear.
3. "What would be the point of biwiring with 2 pairs of cables connected to 1 pair of full range (20hz to 20khz) binding posts on an amp? It seems that you would only be duplicating your existing connection." The point is to use the speaker's crossover to split the frequencies in the cables. The 2 cables may be connected to the same driving terminals, but each cable see hugely different impedances by frequency, so the, say, treble cable of a 2-way is carrying little midrange and virtually no bass, and the bass/MR cable of that 2-way carries very little treble. When I had 2-way speakers with high crossover (as the vast majority of 2-ways are), I used Audioquest KE-6, a 4-pairs-of-solid-silver DBS cable on the bass/MR, and KE-4, a 2-pairs-of-silver DBS cable on the treble. That double cable is now driving my full-range Quad 989s in parallel. (Had I started with the Quads, I would have used just the KE-6.) In a 3-way with low crossover, the bass cable carries little midrange and virtually no treble, so the conductors don't have to be as high in quality but there has to be a lots of them for good bass damping. The MR/treble cable carries the vast majority of the music and should be as high in quality as you can afford. On my center-channel 3-way, I use quite-inexpensive AQ Type 6 on the bass and that great KE-6 on the MR/treble. Biwiring, too, can be complicated, and what cable to use or even whether to do it is quite contentious here.
So with biamping, you get BOTH sets of issues montioned above, besides the possibly complicated issues of which amps to buy and use. Based on what I've read over the decades, I'd say that most audiofiles who STAY with bi- or triamping use amps specially suited to the frequency bands they amplify.