Mixing bulbs is like an old wives tale IME but it has little to do with the reaching. That's just what plants do. Rotating your plants is one way to deal with it and I believe that will help strengthen the stem. It's what I do anyway.
All cool whites will put out more usable light IMO.
It's hard to believe you got every pepper seed to sprout. I can't even get every cell to sprout when I put 2 seeds in each.

Thanks! I didn't know that they usually reached, I'll stop worrying about it then. I did rotate, so I'll keep that up.

I did plant two per cell, so technically there are more than 72 (some sprouted in both, but not all). I got most of the seeds from Baker Creek, and a couple from Seed Savers. Maybe they just have really good germination rates?

I get better germination rates from my tabasco seeds than my jalapenos. The reason (I think) is because I allow the tabascos to turn red and I like the jalapenos green so the prior are more mature. I'm sure seed companies let their fruit mature fully before harvesting for seed.