RL02K Pack Reliability/Characteristics

I've gotten my RL-02 -> USB Mass Storage controller mostly working with a few residual gremlins. Specifically, I've noticed from my testing that I have good packs, ones that read out almost the same every time, and bad packs, ones where half the bits seem to be in different states every time I read them. I've left write support untested until I can solve this problem. Right now, my working theory is that different controllers had slightly different timing characteristics, and I may need to adjust more of my DPLL parameters dynamically to deal with that (something I'd rather avoid). Of course, most of these packs haven't been put into a drive since the mid-80s, and there could be some bit rot going on. As many of you have much more experience dealing with these drives than I do, my questions are: - What type of long term reliability have people noticed from their RL02K packs?1

- Is garbage data sometimes normal for certain packs until they are rewritten with ?fresh? data?

- Has anyone noticed pack compatibility problems between various computers/RL-02 controllers?