How to design a sway bar w/ 3link + watts linkage

[The WidowMaker]

why a sway bar is needed on a 3 Link design?

they arent always needed. but, you may need a sway bar to balance out the front. by adding a rear bar, you are taking some load off the outside front tire in a turn. too tight and you add a rear bar. too loose and you subtract from the rear or add to the front. you can also play around with the rrch, but a bar is good as a tuning aid. thats a very basic explanation, so hopefully the suspension gurus chime in.

a starting point is tough. you might be in a league of your own as far as a setup, but thats the nice part about the splined bars.