....Don't know if
any of this will be of any help to you. Looks like you already have the front suspension set up on at least one of the chassis.

I scratch built a set of offset upper and lower control arms to be resin cast....I used a few references to be sure and get the true and accurate measurements , angles, etc. etc. verses just taking a wild guess.
Before I was able to do the first pour , I built a jig for the upper control arms to keep everything angled properly...the jig is a must, without one the results will ,more than likely, be less than desirable.
Every thing pictured uses Evergreen plastic. The round rod pieces on the upper control arms are Evergreen 221.
As far as spindles go.......
David is absolutely correct on using K&S metal for the spindle. As far as the diameter goes the tubing needs to fit tightly inside the wheel back. If you decide to go with styrene plastic , make sure it fits tight as well into the wheel back and use solid rod, no tubing....I've carved on round sprew pieces to fab spindles as well.