They're around 10-11", so they're getting close.
They've been getting more and more friendly as of late. I fed them twice a day when I first got them, but then switched to one large meal a day for a week or so. They seemed to get less friendly during that week. They'd mostly just lay around or hide under the sand. I've now switched to two smaller meals a day and that seems to be better. They're getting fatter and they are swimming all over the tank.
I think I agree about the light/white substrate. It'd probably brighten the tank up as well, but I'm going to stick with this for awhile. Part of my problem is the sun gets direct sunlight in the afternoon for a couple of hours so I have algae growth. I've bought a 12x turbo twist uv sterilizer to combat this, but I still have a haze on the inside of the tank. I've tried cleaning it with the scrubbers I have laying around, but I just ordered a mag float pro thats rated for 1.25" thick acrylic, which is what my tank is, so the haze should be gone shortly. I also need better lights, as right now I'm just using old lights off old tanks. Once I get that taken care of, it should brighten up the tank a bit.