Torsion Bar Upgrade for '65 Barracuda Formula S

I'm considering upgrading the stock .87" torsion bars in my '65 FS to a bit thicker bar, possibly the .89" if I can find some. This is a restoration, it has the original 273 4bbl, but I am including some upgrades. These include KH disc brakes, 15" radial tires with rallye wheels, and Moog offset upper control arm bushings for more caster. I'm thinking of going with the next size up, .89" if I can find them. Does this make sense or should I just stick with the factory bars? I'm not going to be racing this car, I just want good handling. I know the .89" bars are for 383 applications so I assume the thicker bars compensate for the heavier engine, but would there be advantages with the stock 273 as well, or is it overkill?