Bed plate thread

There are a few threads out there, but I wanted to make a specific one based on my experiences trying to make a bed plate for a short bed that can accommodate mounting gear and cabinetry. There are probably better ways to accomplish what I did, but this was an attempt to locate the bed bolts to attach the plate. It’s unlikely I’ll use the rear-most bolts, since they’re not very tall (even though I have replacements).

The steps I took, including purchasing:
*5x5 Baltic bitch 12mm (maybe it’s thicker; it seems to be)
*floor covering cardboard at Lowe’s

I used the rubber mat as a rough template starting flush from the rear so the plywood would push further forward, allowing more space for edging material. (Explained another way, if the wheel wells were cut further forward of the board, the ply would stick out of the rear.) The 5’ dimension fits the length without cutting.

*used the cardboard aligned to the edges of the ply
*cut another piece that fit the front of the bed
*centered that piece again on the longer template
*laid the full template in the truck to locate the bolts
*placed the template onto the ply, marked, pre drilled, drilled slightly larger, checked the alignment

I used a bright highlighter and made little squares to insert into the T-55 slots of the bolts to see the approximate centers of the bolts. One could use paint or something bright.

After all that, the centers of the holes were not aligned, but the “peepholes” were large enough to recenter the final larger holes with a drill template.

My plan is to use bedliner, possibly edge it with aluminum angle iron (from where)? And predrill t-bolts underneath for mounting as time goes on. Thoughts, comments, ideas, and constructive criticisms welcomed.