The 3.73 vs 3.91 Dilemma

After years, I am now serious about changing out my 3.23 rear for a 3.73 or 3.91. I have a gen III 5.7 hemi (360 HP @ 5400 rpm/360 ft-lbs of torque @ 4200 rpm) and five speed with 3.27, 1.98, 1.34, 1, and .68 gear ratios. My rear tires are 26.7 inches tall. I drive the car on the street and highway and don't want to be buzzing at too high rpms when I get on the highway. With my 3.23 rear, I'm about 1,800/2,100 rpms at 65/75 mph.

I got on the engine rpm calculator website, which says at 65/75 mph I'd be at 2,075/2,394 rpms with 3.73s and 2,175/2,509 rpms with 3.91s. My car before this was a '63 Nova with 3.73s and a turbo 350. I remember hating to drive on the highway with it because the engine winding would drive me nuts, obviously because of no OD.

That said, can anyone with a similar setup weigh in on which may be better...also, is there a rule of thumb for rpms vs comfortable highway driving? Always appreciated:D