I don't have any pictures but I repaired mine twice back when I had an 85 "40". It is no fun. As you have noted the holding tanks are built in under the floor. They are just lids glassed on over the boats stringers. If I recall correctly, to get the floor up you need to remove the settee across from the dining area. After it is removed you can see all of the floor screws and remove the floor panels. The problem with repairs is making them flexible but leak proof. They have to be flexible because ever time the hull flexes it breaks any sold repair loose from the stringer. The first time I repaired them I didn't consider this and the lids broke loose again as the boat flexed. I think the second time I used a combination of 5200 , 4000, fiberglass matting then topped with epoxy. However with all that it was initially to thick and the floor panels would lay down properly. In the end I ground out a small hollow in the bottom of the floor panels because I didn't want to make my repair any thinner. My second repair held until I sold the boat 2 years later in 2004. Not sure how it has held up since then.
