This repair will add some strength. However consider that you now are adding strenght in the upper section of the hull, and not in the lower section. Will this reinforcement be enough to unload the sandwich stringer I can see in the pic sufficiently? A bit late now, but I would have done full bulkheads (hindsight is always 20/20 you know).

Attached is a pic of a ply bulkhead with reinforcements from our Blade project.

I would have taped the half bulkheads to the hull skin to spread the loads a bit more. I would also have cut the holes