started my back half today

i got bored today and decided to back half my truck, the notch was ugly as shit, and mazda frames arnt the nicest lookin ones around. whats the best way to weld the new rails to the old ones, what ive done so far is made it that the new rails go about a foot or so into the old ones, then cap the old rails off with 1/4 steel, cut a hole in the cap (2"x3") then weld that to the new rails (anyone know what im sayin?, lol) then re enforce it more by welding gussets n crap. anyways, heres a pic of it, i just have the new rails sittin in there