If I were you, Gary ....
I would configure the lines the way that works best for you , rather than worry too much about how the original layout was. But then you are not me so you can take that with the grain of salt!
Why not use the port sheaves for the reefing line and the center sheaves for the outhaul. If you had a mainsail with two reef points, I would definitely use the outside sheaves for reefing lines and the center sheave for outhaul.
I definitely prefer to have these lines led to a cabin top winch. I added/replaced blocks at the base of the mast, a deck organizer with four sheaves (each side) and four clutches (each side) specifically for the purpose of having these control lines available at the cockpit with the winches. When we first got our boat, the outhaul was led to a cleat just aft of the gooseneck. This was not useful at all and I also think that having the line exit the boom and cleated on the boom would be useless as well. I have to think that the power in your sail would require that you need a winch to flatten the sail if you are sailing upwind in a breeze and needing to flatten it when overpowered.
How is your topping lift configured? It seems that if you had a configuration like mine you could use the sheave on the sbd side to run the line internal to the exit plate and cleat it at the stbd side cleat. I see no reason why a topping lift can't be cleated on the boom since it is only necessary to use it when you are dropping sails. OTOH, I agree with Roger that the slack line hanging below my boom is bothersome and a potential hazard (I hadn't looked at it this way because our conditions are not ever rough).
We don't have winches on our mast (as you can see), so our halyards are run aft to the cockpit. I like this system better. Even though I have to go to the mast to hook the reef tacks, I marked the halyards so that I drop the sails exactly to the point where I can hook the tack with just enough tension that I never have a mishap when going back to the cockpit to tension the halyard again. I've never missed yet so it works for me.
Bob, I have not seen that sketch either. That is probably how the PO's did it on our boat! I think that next year I am going to change the lines so that after passing through the cringle, the reefing line goes down and under the boom before coming up to the cheek block and over to the eyestrap. I'll see if I can pull that cheek block back into its original shape!