[Skaggydog]

I have the factory wood floor with vinyl garage floor cover on top. I did not want to dig through the flooring to make a solid bolt up but I believe this will work as long as the bolts stay tight.
I used 1/4"x3" A36 flat bar with 5/8" & 7/16" Grade 8 NF bolts. I removed all rust and mill scale from the plates and sprayed on cold galvanize. Cold galv, works very good if it’s 95% or more pure zinc and applied right. The bright shinny 50% or whatever, not so much. I also sprayed the holes I drilled in the floor.
Now I have the bed in, the floor covered and an extra seat. Installing a Fantastic Fan next.

 

[RDinNHandAZ]

I am with you. I look at the bolts and anchors on factory installed seats and cannot believe yours won’t work. But then I am not an engineer nor have I done a strength analysis so who knows. I’d be willing to put my grandchildren in that seat though!