subframe connectors

i'd just mig weld them. i'm a welder (when not in school) and i think it should be plenty. did mine with mig and i had the same options. overhead tig is a waste of time imho. And i think the material you are welding to is too thin to be using stick. mig FTW!
i have done a lot of industrial fabrication, and properly done mig welding is very strong. Strong, easy and fast. Great stuff.