C notch help

I'm goin to use 2x3 tubing but not sure on what thickness to use I will be towing a30ft camper and 23 ft boat also how tall does it need to be to clear 24s

I used 3/16 thickness. Height depends completely on how you plan on setting up the rear. Bags?

Bags on outside of frame on top of axle next to notch

Ive always used 1/4 inch tubing....might wanna look into some 3x5 tubing just to be alittle stronger.....and also plate the frame at front and back of notch....sounds like a good bit of weight and you dont want that frame warping