I used 14" QA1 #150's on my old zuk running a 3link front/4link rear,scout D44's,5:13's,calmini 6:5.1 gear's,37" pitbull's....It was alittle soft but rode like a fluffy pillow.I daily drove mine and it was the best riding machine I've been in,even down the highway countless time's at 65-70 with no wandering what so ever,tracked great.
Try to mount the coil's on the side of the frame(make's it waaay more stable/handle's corner's ALOT better) plus a lower ride height is alway's good,I was at 20" from frame to ground on 37" pitbull's
Use a link calculator help's in design of the link system---I like to be around 70% AS with as close to 0 on the roll axis. 70% between the length of the upper's and lower's and try to make the link's as long and flat as possible.
I used Johnny joint's at the frame and bushing's at the axle's.I run 2x2 .25 wall for lower's and upper's,never had a problem with the suspension and I beat the hell out of it.