Steering question and advice

[18tahoe]

Just finished a 55 2nd series truck with straight axle and Toyota power steering. Rebuilt the front end so everything is good there, the problem is that the truck seems to wonder a lot, not pull like a bump problem. I had the front end checked and right now there is 4 degrees of caster, should I get this to 6 degrees. The shop said they set the front tires straight up with no toe, would some toe help this problem. I want to make the truck a little more stable so any advice and suggestions would help. Thank You