Most efficient reinforcement between main hull and conning tower

[Sub596]

Hello

For a submersible using ASTM B265 Grade 5 titanium
42.0” OD hull, 1.0” thick hull with reinforcement rings spaced 28” on center
Having a conning tower 25.0” OD, 0.75” thick

Question:
What is the most efficient reinforcement geometry between the conning tower and the main hull

Thanks