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I am looking to add in new basking areas in my tank and am looking for some suggestions on material and support.

Suspended as in hang from the edges of the tank, or elevated with risers from the bottom of the tank?
Wood (untreated), plastic, ceramic, stone?

I have a 125 gal with approximately 85-90gallons of water in it, I have two RESs that are both about 7 inches in shell length.
Tank is a bit on the small side, but largest I could get for a low price.

If you want to maximize the tank, you'll want something above it. It'll also look "cleaner" but it requires some basic skills to make. An in-tank PVC/ceramic tile platform will be ridiculously strong, will not wear down, and can be very inexpensive. Depending on how high you want the water level, it might need a simple barrier to prevent escapes.

After looking at various builds, I decided on what you said. Sort of a platform that hangs from the sides of the tank. The frame is 1/2 inch CPVC and plan on using 1 inch untreated white board, mainly as I have some left from a project.

I didn't suggest anything on the side but it's doable. It takes more space but offers more creative opportunities.

No, but I thought to have the platform hang from the inside of the sides would work. I'll post pictures later.