Please don't take this the wrong way, but you might just need to get more comfortable riding your board. Getting comfortable riding around a park, dropping in, hopping up and down curbs and stuff does a lot for your confidence, muscle memory, and overall confidence on the board, which translates to stability (if I'm understanding what you're saying about stability).
That doesn't mean don't think about how your board is setup, but it sounds like you got your shit pretty damn tight now and you might want to just focus on building that muscle memory and psychological comfort on the board so you don't need your shit so tight to feel stable.