That will probably work, yes. I doubt anyone here actually knows that turbo yeast represents a single strain, but it would be pretty surprising if it didn't.
Why you would want to do this, though (unless just for the hell of it) is completely beyond me. Turbo yeast isn't expensive, and if his yeast cake is from a high alcohol fermentation then it is already as pure as what you'd get from this. Your method for selecting for the turbo yeast is to plate it on high alcohol agar, presumably assuming most other things will die. You're probably right, but you're taking it from a high alcohol liquid! You're not actually going to be accomplishing any selecting here, or from the opposite angle, the selecting has already taken place within the wort.