In any case, the EDDIE study indicated that for my system that combining the primary and secondary runners after they exit the block not only would probably not hurt things, it might help.  Well, it certainly simplified the tube alignment problem and we will see about its affect (if any) on performance.

This puzzles me, and maybe I missed some prior part of this discussion; but how do avoid getting a wave reflection; degradation or whatever at the junction of two into one?

Al