I've been advised to alter this so that the halyard does not run to the rear beam.]
I second that advice. I sailed with a rearbeam setup for about a month and then changed it.
Best in my opinion is to tie a bungee to the rearbeam and tie a large stainless steel ring to the other end. This ring must reach somewhere halfway the tramp when the bungee is tensioned somewhat. Run the spi halyard from the grommet to the ring and then back to the clear on the mainbeam or the guiding block there (mast based cleat system). Now you can always face forward when hoisting and doucing the spi and the bungee will take up the slack.
Better still is to fit a small block to the rearbeam (or again a stainless steel ring) and ring the bungee through that and tie it off somewhere far away. This allows the ring at the end of the bungee to move with the halyard over large distances wihout changing much in pulling force.
Work well for me. I've never sat on the halyard since I made this mod.
Additionally, I too favour the single line setup for 1-up sailing over the 2 line setup.
Wouter