5 or 6 leaf rear springs?

Just want a nice handling road trip car, not a solo racer that rattles your eyeballs, so this is what I have so far on the car.
Its a 318/904
T-bars are same as what the 340 had, I think they are quite stiff, and handles pretty good without a sway bar even.
I've got a skinny factory 7/8" front sway bar, it was free.
The rear is still original 4 leaf and I've always thought too soft, barely stops the arse from dragging.
My other dart street beater (avatar) has stiff 6 leaf springs that hold the rear up high, but other than speed humps the ride is not too bad.
Should I go with the same dearched for the road car, or some 5 leaves?
I'm thinking the 5's but then again those 6's have really kept the rear axle under control, braking and accelerating.
What do you think, any spring brands you trust?