Running boards

So in another thread I posted how I bought double cab boards for my access cab. Yup big mistake realize it now. Buddy of mine has flaked out and isn't available to help figure out how to install them.

Long and short the factory holes are all kind of jacked so I'm abandoning using them as is. I have a cheap harbor freight drill tap deburr kit which goes up to an M10 size. Regular size is M8 1.25.

Does anyone know if the reinforcement along where the factory bolt holes are runs the whole length? If so I'm thinking I'll drill and tap my own M8 holes. If not my next thought is to enlarge/tap the factory holes out to M10 and get M10 bolts washers and lock nuts.

Only 2 of 3 brackets line up to the threaded nut inserts on the boards. Thinking of investing in a nut riveter or similar and making my own mounting points on the boards to line up with the last bracket mount on the truck or just run a self tapper in to the boards.