I don't know if this helps w/ your question, but figured I'll throw it into the mix. My experiences have been w/ different carbs on my 440:
1. A Holley "950 HP" was good enough to get my car down to the 11.0s. Nice carb, even though Holley claims a bogus flow #. My experience mirrors others I've heard about how they improve 60 ft & ET compared to a traditional 850 because the smaller venturi (1.375") is more responsive and recovers better after big RPM changes after shifting.

2. My Claw configured w/ 1.42" venturi & downleg boosters (what BG calls an 825) was worth 5-8 HP over the Holley "950 HP" on the dyno. The Claw was also quicker & faster on the track by about .05 / .5 MPH. Jetting is different from the OOB settings courtesy of dyno time w/ PRH.

3. When I configured the Claw w/ 1.56" venturi and annular boosters, it didn't run any faster on the track (not sure if it actually ran slower, though) and ran worse on the street 'cuz this combination pulled too much fuel at lower RPMs. I've found this is a common complaint about annular booster carbs on big-block engines and doesn't "tune out" easily. If I try the annulars again, it'll be w/ a 1.59" venturi.

4. I haven't had a chance to try a 1.56" venturi / downleg booster combination. My concern is that this may loose too much booster signal and soften the car's 60-ft. compared to the smaller venturi config.

Know anybody w/ a Holley "950 HP", Quick Fuel 950 or Proform 950 (1.45" venturi, IIRC) you can borrow? If you're limiting your choices to what you can find used because of budget, IMO you really need to be able to test before you buy to make sure the carb you end up with is actually an improvement over whatever you have now. BTW, what do you have now, other than the borrowed Holley from Mr. P?