DIY floor pans.

To each his own. Here in manitoba, all repairs in floor and rocker area now need to be welded in,with same gauge or thicker metal.
If i take a car for a safety inspection,and they find rust holes, the repairs done need to be inspected and signed off by a body shop.
The insurance company are starting to get anal about proper repairs.

i will admit in the past i patched floors by whatever means necessary,with what tools and materials i had on hand. But i never used plywood!
However i have seen it used.
Over 30 years i have advanced in skill and tools,and i still have second thoughts over purchasing formed panels to repair a floor.
Usually never a restoration, but a repair.
Restoring it? Perhaps to sell,the repair should be top notch in my opinion.