Well. A tutor that shows you where to place your fingers should probably have lessons suited to the layout. So I don't think there are many of those that are customizeable?

However, once you're started with a layout you won't need visual guides. I've used Amphetype a lot. It's not a tutor as such, but well suited to training.

I've had fun with Typing Of The Dead, which only to a small degree supposes that your keys are in certain positions. Some tests will be more difficult than intended in the start, but then some will be easier.

If you like Colemak, you could use Tarmak which doesn't require you to use a tutor as you only change a few keys at a time and can type normal text to train.