Hi Tom ..Had a quick look at you attached drawing ...Looks like legs of appx 2" x 1.25" ...? cant make out the section .. Material you state above to be 4130 ? correct .?
Must point out that I am not an expert stress man and so take this mearly as an informed ( or not ) opinion only .........FWIW...
From first glance the joint where the leg meets the lower fuselage tube , looks a little weak on the taking of the compressive loads associated with this junction .
I'd say that the longeron tube , ( presumably of Allum. alloy ) , could do with either an internal or external liner / sleeve to spread the load into this component to avoid local crushing .
As to the actual leg , ...the strap idea is fine for a tension but not so good in transfering the compressive loading and again could be treated somewhat as a strut end , by adding a (welded on ) saddle to the end of the tube , perhaps even with a plate from it , slotted down through the centre of the leg for some 3" or so , and welding .
This would greatly increase the bearing capacity of the joint .
I have done a couple of very rough sketches of the bits you asked for ...
Rather than go through the photobucket bit for everything , which takes a while , ...If you send me ( Via a PM ) you'r e-mail address , I can just e-mail you the sketches , which saves a lot of messing about .