The standard grip is 1 3/4" deep (belly to back). String to the back of the bow adds up to 28", putting about 26 1/4" to the deepest part of the grip. This makes sense when you think about it as with a broadhead mounted the back of the bow will act as a draw check.
Also, if you're getting lighter limbs, you may want to hang onto the heavier ones in case you want to upgrade in the future. Or, as a backup in case the lighter ones fail or something. Be almost like having two bows. If you can/want to afford it.
Just suggestions/comments. How's it shoot?