Custom does have a different strap it's called the Lush strap. I haven't ridden it, but I know the superstrap and asym superstrap on the missions/malavitas and cartels are pretty darn comfy.
Also, Alka is right, you can make any binding work on your board (I do prefer to be on the stiffer side than the softer side though), it's preference. There's no ideal matching.
I say missions/cartels. The hero you have has squeezebox so it can't be softer than the hero I demo'd in 2011 and the bindings on those were the Missions which, that year were pretty stiff...rode great.
Not to be a cynic, but you'll also be able to sell those more easily than the customon the ebays or craigslists or right here, if you want different bindings.