I made a set of long arms with square tube
I made them non adjustable becasue I had the llenghts figured exactly and I made the uppers adjustable for changing caster /camber..
what I did was bought a coupler nut to fit snug inside the the sqaure tube (with a little grinding)
and I bought 2ft of threaded rod
for the uppers
I left about 1/4" sticking out of the tube to weld them to the tip of the tube and also bung welded them at 4 points .
side note here .......I had the square tube laying around the house as scrap..
then I decided to go to DOM
with 1.25 HREW sleved internally (inside of the DOM)
the thing is for the price of an entire stick of 2x2x.25 wall sqare I could pick up 7 ft of DOM and use my existing uppers ..
eventually I changed the uppers to DOM..not because of failure I just wanted to change out the bushing tp poly and I figured it would be easier to shape th round tube with my tube notcher..
ps I did all the shaping on my frist set with a grinder
the second I bout a HF tube notcher and some goood bi metal hole saws
way better cuts!!..
I caught a lot of crap for having aquare tube as control arms ..
.
either way I would defintily sleve em If I were you ..