Which model? Onc the web gets long enough, they worry that you are going to try to catch a line drive baseball and it will go through the holes and hit you in the face. So they will really want to add another cross bar at either the base or in the middle (see below). The size of the holes only goes up when you add width.
In general though, if you want the web to play deep and wide, I'd ask for the top bar to be 5" wide, the middle bar to be 5.25" wide, and the length to be increased 1/4"-3/8" from what they would normally put on the glove. You have to add some length or the web will play wide, but not get as deep.
The dual hinge web on my 504 is 5" wide at the top, 5.25" at mid web and is 1/4" longer than the usual H-web they put on them (with a width of 4.5").