The best way to go about the situation (for potency and flavors) is to inbreed your F1 to make F2. Only 25% of the F2 will autoflower, but you will see definite increases in potency and aroma by the F3 compared to if you were to backcross to the autoflower parent. Of those F2 that autoflower, breed a male and a female together and by F3 you will be fully autoflower. You will still have to stabilize plant structure, but at this point you're more potent than if you had taken an F1, backcrossed it to an auto, and bred the resulting autoflower offspring. Both scenarios take 3 generations, but the difference being that the backcrossing shortcut will give you 50% auto compared to 25% auto at the F2, but inbreeding gives you more potency and aroma, even though you see 25% autoflower at F2.
NOW, once you have a fully autoflower male from the F2 - branch the line off. Breed two fully autos from the F2 together to have a fully auto F3 but ALSO use an autoflowering male to backcross to the photoperiod female. You would then have a 3/4 cheese and 1/4 auto. If your F2 male was average at 16% (based on the hypothetical numbers above) and your photoperiod was 20%, this line of seeds would have a median potency of 18%, but you would have to inbreed to F2 to see any autoflower.