Two coats of Red Oxide primer paint
One coat of Hammerite black paint
I don't like messy open-ended box section
Blank everything off where possible
... or weld a plate over, also doubles as a foot pad
Clamp down the panels ready to drill and tap
Drill through with pilot drill, then tap
Far neater to just use bolts, than drill all the way through and use both nuts and bolts!
Treat the wood with stainer and/or varnish
The finished article !
THE END !