Friggen monstrous arms Rob!!!
It's rather difficult to argue with those results

I didn't find incline DB curls useless. I think it's a decent, maybe even good, biceps exercise.
The trouble with them is not so much the movement itself but what it *is supposed to do*; i.e., emphasize the stretched position of the biceps.
Doing so is a good thing according to recent research. I can't speak to all of that, but I can say I did some mighty strict incline curls with respectable weights for a decent rep count (12+) to failure. Curiously, in the bottom position, even when my biceps felt like they were tearing through my skin with a pump, I *never* felt a deeply stretched sensation.
I did achieve that with some cable curl variations, but I can't speak to their efficacy because I got sick shortly thereafter :/
Assuming I ever get my hernia fixed and get back to the game, I'd probably go with a decent preacher machine curl and hammer curls. For anyone injury free, I'd recommend straight bar curls and hammers. If you can get to the point of curling a decent percentage of your bodyweight with an Olympic bar for 6-8 sorta clean reps, you're going to have some huge biceps!