Oops, almost forgot. You mentioned difficulty in withdrawing the rocket shafts. A common malady, many posts covering that, and MikesXS even offers a tool for pulling those rocker shafts. But, that ain't supposed to be. An excerpt from the manual:
View attachment 121154
On my other XS1B, the rocker shafts do indeed slide out easily. On some of the camcovers I've recently acquired, the rocker shafts were very difficult to withdraw, and produced semi-circular aluminum shavings just like in your pics. The rocker shafts have very narrow support in the aluminum camcover, and seem to get hammered upward, which swages the aluminum around the outer edge of the rocker shaft. Withdrawal requires that the rocker shaft shave off this swaged aluminum, since it's blocking its path.
When I reinstall the rocker shafts in those camcovers, I can get up to 0.010" vertical slop in those rocket shafts. I'm suspecting this adds to top end clatter, plus other anomalies, like the uneven/slanted wear patterns I've seen on other posted pics of rocker pads.
Been contemplating designing some sort of tooling to bore-out and bush those rocker shaft holes in the camcover, but that's another long project.
Anyway, just wanted to let you know the probable source of those thin shavings...