Miata based tube chassis

I've recently acquired a unfinished 4130 chassis, it's all tacked together, I have to complete the welds, then finish building the drive train.

The tubes have some surface rust from sitting around for a few years, I'll be able to clean it off with a wire brush and some fine grit sandpaper, but wont be able to clean the inside part of most tubes since all is tacked.

Will the weld quality suffer a lot from this ? not a lot of reading material about this, most you see people just clean the area where they tig from, and not often the backside so I lean towards sending it and not worrying too much, but having some second advice would be nice.

From the minor external corrosion, it shouldn't be a problem.

It is a strange looking thing with what appears to be dual coil-overs on each corner? Originally I thought it was using a Jag' rear end, but on closer inspection they seem to be in line, rather than parallel?

Thanks for the reply

I'll probably redesign the suspension to be inboard since this will mostly be an autocross / track toy.

I have another set of dual buggy coilovers with big chunky tires to go offroading, I've never offroaded, but may try them in rallycross or just dirt roads.

The rear end is made of the following bits : Miata diff, subframe and uprights, custom axles and Paco Motorsports control arms (much wider track than miata)

Front wheels have been moved forward by a lot, engine pushed back, the closest thing would probably be a fat caterham.