An ELB is so long you have a bit of leeway, but I tend to stick to the good old 1" above centre for the arrow pass.
The belly of the bow just swells slightly at the handle area, there is no narrowing or cut away arrow pass or shelf.
The back can be a bit flat for cofort, so I sometimes build up the back slightly with some leather for a more comfortable grip.
A folded over edge at the top edge of a leather grip may help in locating the arrow if you are used to a shelf.
Del