Thanks for your input. I'll likely go with the spacers. I thought about reinforcing the 1/2" thick plywood with aluminum angle bar attached underneath but am concerned that if someone or something heavy happened to break the plywood you would run the risk of puncturing the fuel tank.
The fuel tank cover (25" x 63.25") on our 1988 Seville Bow Rider needs to be replaced due to the plywood delaminating along the edges, causing the flooring to sag when you step on it. The aluminum angle bars are in good shape and securely attached to the stringers. The existing cover is...