I'm curently makeing a bunch of bits and bobs at work.

and am about to embarch on a caltrac like set up?

Is ther any need advantage to having lateral control on the rear buy Ithe triangelating the two bars or having a tird diaganel bar?

will hav a whiteline sway bar.

Reasonably soft springs probly only a little harder than original.

and whats the best shock for the rear in a sedan?

You are right, diagonal arms are better than a panhard rod for most applications. The latter is a cheap and adequate solution, but not optimum.

I intend to keep one leaf on each side, and fit up a pair of adjustable coilovers, Caltrac with diagonal arms too. It just eliminates the extra force by spreading it more evenly.
Ty