Years back a old school BB'er told me that he had been doing the standard BB curl, with heels on a 2X4, and it seemed to help with the focus on the biceps. Saying that he did feel better balance and even increased the weight he was using. He had also done overhead press and upright rows, with similar better results, the the 2X4.. Which only proves that BB'ers are among the most inventive, and willing to just about try anything, group around. This guy had pretty big guns at the time.
I tried the 2X4 thing with some BB curls, and it did seem to shift the weight, give better balance, with more focus on the biceps. Than I did upright rows. and noticed quite a difference than when doing them flatfooted. Don't know if this would work for everybody (nothing really does) giving different body types/bone length/muscle inserts, etc....but for experimental reasons, might be worth a shot.
Only time I use a 2X4 is when doing BB Hacks. With regular and front squats, raised heels don't allow the full potential of the ankle/calf/foot flexibility. that the flat footed version does. If into sports, the ankle/calf/foot flexibility is of prime importance. If into BB'ing, raised heels will target the lower & upper quads very well. Good Luck.