Is it a 750 vacuum or mechanical?
The carb is not too big, just out of tune.
The jets don't matter at idle.
You need to get the idle screws (in the side of the primary block) set first.
It's a bit of a balancing act, because those idle screws will also move your idle rpm, so it takes a while to get the screws tuned properly along with the idle speed screw tuned properly. If you adjust one, and it throws the other out of tune, you will have mixed idle stability like you describe. I like to think I am good with carbs, and this is one area of tuning that gives me fits.
Your "over 2500 rpm bog" issue could be jets, but I suspect you have a vacuum secondary and the secondaries are opening too soon.
If you have mechanical secondaries, then your bog is an issue with secondary pump circuit tuning.
You pump circuit tuning is where you get to take advantage of a carb's awesome throttle response.
The Holley accel pump tuning involves pump cam, lever arm adjustment, and shooter size.
If you have these out of whack on primary or secondary pump circuit, you'll have tip in issues (primary) or mid-rpm range bog (secondary).
Give us a little more info on what carb you have, and we can narrow it down.