You don't have to worry about hull strength with the thickness down there. Just make sure YOUR HULL and ambient air is at proper cure temp at the time of installation and will remain that way throughout the cure. You may want to construct a simple tent that covers the boat in that area and run a string of lights to keep above the min curing temp both inside and outside the hull, day and night.
If I were you I'd use 4000 rather than 5200 simply because removal, should you need it, will be significantly easier. The sealing properties are very close.