Punchy Dan:
When you see containers on a flat with straps over it’s usually because only 2 of the twist locks are usable/ line up .
I carry containers on my flat I put 2 straps over but use 4 ratchets then also diagonal on each end from top corner to opp on the side rail .
You mean opening the doors and nailing thru the wood floor into the wood floor of my trailer ain’t right? have to change my ways!