Mounted my C60's to my T7 at the start of last season... Tightened them down with a cordless drill with the chuck set at about 2/3rd tension (a little tighter than I'd be able to do by hand). And they haven't loosened since and that's with 51 days of riding, and riding hard.
The outline of the channel does poke down into the base, and when waxing you can feel it when you scrape over the area, I usually have to hit it with the texture pad a little more to take off the extra wax. But it doesn't appear to affect on snow performance, I seem to keep up to everybody pretty good.