If u cant tig weld that well I would just tack up the cage and have someone more skilled lay down the welds.
NHRA will scrutinize your welds to make sure u have adequete penetration and if your welds dont "look" the part u may have an issue passing. You also cant grind down the welds as far as I know.
I do "some" welding but I know when to call someone in for help.
Why take a chance?