One small issue that you can have with a slitting disc in a Dremel-type tool, is that, if the disc is of a smaller diameter than the body of the drill, then you will not be able to cut the track with a perpendicular face. This is not a problem, if you have the body of the drill over the piece of track that you want to retain - the slight slope will then be in your favour and the joint will still close up at the top , the small gap will be at the bottom where it doesn't really matter. If you cut it with the body of the drill over the 'waste' piece, then you'll get a slight gap at the top of the joint that can't be closed up, as the joint will butt up at the bottom first. No big deal, but worth keeping an eye on.
A bit of clicky-clack is no harm, anyway.