Attwood was very responsive, but the bottom line is that the user/builder/contractor/etc is responsible for design and sizing. they didn’t address my question as to why the piston relaxes 2″ now rather than the 1″ originally. in fairness it was 10-15F cooler the other day than it was when I originally installed, so the ideal gas law would predict some lesser degree of pressure exerted by the piston at lower temps.
CLC determined that 20# force was sufficient, and I assume they were reluctant to oversize the force since the tradeoff is more opening force = more closing force on the hinges.
having said that, I believe 30# gas springs are desirable over the 20# ones supplied.
ken