Yea, I thought about beefing them up but I have seen some little gussets like that hold things you wouldn't believe. I'm having all those laser cut from one of our material suppliers for super cheap, so making them a little bigger wont cost me much. I'm still looking around for scraps & drops to piece these together. We have one of our fab shop owners coming in today for a meeting on a new job & I'm gonna toss him a print & get a quote for the welding since I dont have a welder myself.
IMO ditch .250w tube, you're just making the rig heavier for no appreciable gain. Run some .120 or .188 if you really think you need it. Run a .120 gusset from as far outward to as far upward as you can with a 1" wide .188-.250 strap welded along it's hypotenuse offset equally and it will be fine.
My sliders are entirely .120w, my rear bumper was formerly all .120 (before I back halfed it) and it works fine on the rocks. The only time they deform is when I drop off multiple foot ledges I should have been paying attention to. Even in that case I just get a shallow bend.