Your angled supports are too small. The heat from the weld will be too localized on the frame. At the very least, you need some triangular gussets to go between the top of the leg and the frame, otherwise you will be beating them down like we have to do with Molly's.
I totally agree with this statement! You will want gussets, and your L brackets will not reach high enough on the frame to do so as they are know.
If i were to do mine again i would have made my L brackets a bit diffrenet. I have plan jane L brackets that are welded straight up the frame, i have heard that this is bad and that i may have some frame fatigue problems in the future. I have heard that a diamond shape on the frame would have been better.
Also as far as gussets i would not just put a flat piece of stock in the middle of your leg and then up to the frame, i would (did) use 2x2 cut in triangles and then notched to fit the legs. The middle of the leg is the weakest piece of that part, so instead of doing what a gusset should do, its really not going to do anything at all other than dimple the leg where it is attached. (if you had round legs a single gussett in the middle of the leg would work, square stock all it does is look good and take more work to complete)
I dont have a good pict of the under side of my truck, but if you look at the sliders here you will see my gussetts.
(please disregard the rust on them, i never painted it after mounting them, so now i have to go back and fix that.....one of these days)
And yes they move a bit, but not much more than maybe at most an 1/8" (I bet its closer to a 1/16). I have had the full weight of my truck on my driver side slider. No defelction and i slid down about 3' before hitting the slider at damn near full speed. Strong gussetts = little to no movement.
the second outer bar......You can always add an outer bar in the future, i will if i ever decide it needed.
In any case props to you for making them!!!!!!!!!!!!!!!!!!!!!!!!!!!! Keep going, you will have changes and changes but in the end you will be super happy with what you have created!!!!!