You are not mistaken!
Yes, we've raised CX the last few years.
We've tried three different hatcheries, Metzer, Meyer, and Welp. I'm not familiar with there being different strains of CX, but the batch we got from Metzer did the most poorly. We did brood that batch differently than rhe other two (in an outdoor building on dirt) instead of in our basement but otherwise everything was the same. Could have been the different brooding environment or just a coincidence, idk.
Seeing as you're in Alabama, I would raise them during the cooler weather, as cool as is reasonable. They are not heat tolerant at all. They need lots of ventilation, shade, and water, and sometimes it's still not enough and some will have a heart attack or heat stroke/exhaustion of some kind.
I love your thinking about feeding 12 hrs on and 12 off. That's what we did, as well. Our birds were definitely more lazy than our layer chickens but we haven't experienced leg issues or extreme laziness that I've seen others report and I attribute that to not giving them free access to feed 24/7.
You may think now of processing at 8-10 weeks but be open to processing sooner. Sometimes they get bigger quicker than you think or some may not be doing as well in the heat so best to get them processed earlier.