I think I've finally found "my bass". My Modulus Bassstar neck on a 2000 MIA P body. That leaves me with the P neck to be stored until I find an interesting donor body for it. My question is: should I do anything with the truss rod while the neck is in storage? Loosen it, perhaps? Does this matter? Maple neck and board.
It's an open discussion, but I would say loosen the truss rod for storage. The truss rod is for counter-acting the tension of the strings. When the strings are off for a while, why counter-act tension that isn't there? But that's the theory. No experience on the topic.
I don't know this for a fact, but I would be willing to bet that the neck's wood might be slightly more prone to moving in funny directions if it's left off of a body for a long time and not being acted upon by the counteracting forces of the truss rod and strings, even if the truss rod is kept loose during storage. You probably have a bit of time before it starts to move, if it even does, but I would start to wonder about warping/twisting if the neck was left off of the body for more than 6 months or so. That's just my opinion however, and isn't based on any sort of scientific findings or facts.
Xylem, there does seem to be a bit of logic to that, though, like you, I don't know enough to say for sure. Anyway, I took a penknife to the pocket of my ESP (modulus) body, and scraped the paint where it just overlapped into the pocket cavity. This was just enough to make for a tight fit for the Fender neck. The body would need to be slightly notched to allow for a truss rod adjustment. So, I think I can get both of these back in the game.
I usually take all the tension off the rod, and then re-seat the trussrod nut back just at the point of adding tension again, to keep everything in place. I'd wrap it in some manner with some dessicant packs or whatever, and store flat. Just my opinion and experience.
Nice! How convenient that the ESP was able to accomodate the neck. That's pretty cool that the bass for you turned out to be a hybrid like that.