Fixing my rotten floor on flats bay boat

I would appreciate your knowledge in helping me accomplish this job with satisfaction. First off, I have a 20 foot flats boat, a scooter (no sides). I removed the floor and am planning on replacing the stringers as well.
1. If I use 1/2" marine plywood do I need to seal the bottomside (underneath) with resin/epoxy?

2. If I used CDX and seal the underside as well, will it last 5-10 years?

3. Being that it is a flats/shallow water boat how many layers of fiberglass mat would be suffice. I was thinking 2 layers of 1.5 oz. for the floor..

4. What type of wood could I use for the 1x2" stringers. I was thinking pressure treated 1x4 pine, split down the middle....

5. Lastly, if I used polyester resin to coat the underneath of the floor what could I expect?

Thanks in Advance

 

If you search on this forum for stringer replacement you will find all you need to know.

 

Thanks for your input Jim. I have searched the forum, but couldn't find anything as listed below. Otherwise I would not have posted this question...Thanks again for your abundant knowledge.

1. Specific to a flats boat (in other words, less weight the better)
2. An answer on the amount of layers of fiberglass