With the new trunnion models, it might be worthwhile to look at adding support for this mod:
https://github.com/meirumeiru/PayloadRetentionSystem-Next
While it's functional, its trunnion models are low quality. The new models are much superior, and with some modules, the trunnions are integrated into the model, so the adjustable pins are not needed at all, just the appropriate node.
I'm not the author of the following patch, in fact, I don't remember where it came from, but I've been using it and it works.
PayloadRetentionSystem.cfg.txt