I came across this article on pressure vessel design which may be of general interest.

Pressure Vessel Design — Half Cat Rocketry
https://www.halfcatrocketry.com/pv-design


Direct link to the PDF;
https://www.halfcatrocketry.com/s/How-to-Design-Pressure-Vessels-Propellant-Tanks-and-Rocket-Motor-Casings.pdf


While it specifically addresses the design and sealing of pressurised oxidiser / fuel tanks of small amateur rockets (ie. keeping high pressures inside), there is a good description of sealing methods, pressure ports types and analysis of potential failure modes which may be relevant for WTC design