Help me pick a gear for my combo

Hey guys, I got a pumped up small block in my 72 duster, 904 auto trans, tci 2500 stall converter,b&m pro ratchet shifter,trans go tf2 shift kit, 28" tall rear tires, 8 3/4 rear with 742 center section and a clutch sure grip.4.56 gears

Here is the thing, Ive been restoring the car over the last 4 years almost and have only got to drive it a hand full of times. But im close to having it ready for the road so I would like to figure this out soon and get a clear idea of what I should be doing.

The Duster is a BEAST of the line...super fun. only problem is.....from what I can tell, its going to be clinging pretty high up in the rpm's at back road cruising speed of 45mph-55mph (not to mention what kind of rpm's it would be running on the highway if I were to ever decide to take it on the highway that is.).

so I am looking for some input from people who have basically the same driving needs as I do and what setup they have similar to mine and how it performs?.

Im mostly going to be doing around town cruising , and lots of back road crusing (45-55 mph). Id like to be able to occasionally get on the highway if need be and without having to listen to my engine screaming towards red line lol. I also would like to be able to take it to the 1/8th mile or 1/4 mile strip at some point. not to mention with the 4.56's running high r's so often at higher speeds I am sure it will ruin what gas mileage I might be able to pull out of it lol.

so what would be a good all around gear for me for my setup...keeping in mind it will mostly be a around town cruiser that wont see alot of highway driving and that may see an occasional trip to the track. and I still want that seat of the pants performance feel.

3.55?, 3.73?, 3.91?

all info is appreciated ,thanks in advance guys.