I would think the the delivery does have an influence on the break of a pitch. Especially like you mentioned with having a sub-mariner deliver a 12-6 curve. Even a change-up would be different.
Whenever I make a SP, I make him 6'10" wearing #51 with a 4seam and slider as his main pitches. Mr. Snappy (as his slider was affectionately called) is always a threat. And Yes, I still have the video of him coming out of the bullpen in relief with Welcome to the Jungle blaring saved on my computer.