DIY Tubular A-Arms... Tubing sizes and Cross Arm Suggestions?

[theastronaut]

I'm getting ready to build a set of A-arms for my '66 C10 with a stock crossmember. I'm wanting to move the wheel forward 1", add more castor by raking the ball joint locations, and make a dropped bag pocket so I can shim the bags with 1/8" and 1/4" plates to change the bag height/pressure without changing the ride height. That way I can fine-tune the spring rate easily. I'll be autocrossing the truck eventually so I'd like the added adjustability over A-arms that are available, and I want to try building them myself for the fun of it.

I've been searching and it looks like 1.25"x.190 wall is pretty standard for the bottom arms, and 1.0"x.190" for the upper arms, but wanted to double check before I bought tubing. I'll be using DOM mild steel tubing. I can't find anyone that sells cross arms, upper or lower that would be suitable for DIY arms that mount to the stock crossmember. Any suggestions? The ball joint cups and upper B/J mount plates are fairly standard so I think I can get those from Speedway.

I've pulled measurments from my stock arms to go by, but can't get started making jigs until I have the cross shafts and ball joint plates and cups. I have 4"x4" 1/8 wall tubing to build the jigs.