That is exactly the kind of "repairs" that to me devalue a good boat. Do it right, take pictures, make it better than as built and the boats value will not be affected. Pull up the teak, cut out the rot "all of it" replace with new marine fir plywood and completely seal everything with CPES. There is no way to know the extent of the degradation until you gain complete access to it, and it will be more than you think. Epoxy injection is for ametures, it never works as good as you think it does and the cancer keeps spreading. Eventually the area will just fall thru. I do agree that it is a good "quik fix" and will slow the deterioration of the area for awhile. I also know that the quik fix usually ends up not getting permanently fixed. CPES is probably about the best epoxy for doing this as its very thin and will really soak in, even in saturated areas. It really smells so dont use it if you cant leave for a few days.