When adjusting rocker arms after installing a new cam, is it recommended to do it with the engine running, or by manually rotating the engine to TBC on each cylinder etc. I'd like to avoid the oil mess if possible. - Thanks

You need to have the rockers adjusted BEFORE you break in the cam. I usually do it by adjusting each cylinder with both lifters at the heel of the cam, then once it's broken in, I go back and adjust them running just to be sure -