I have sailed an infusion for over a year now, and find the simple outhall system fine. This is mainly because I have two settings, one for flat water and one for the sea. I don't know of any top F18 sailor who adjusts the outhall while sailing, so why does it need to be adjustable? Especially when pulling on the cunningham effectively pulls on the outhall too to flatten the base of the sail upwind.

The rope does snap easily, so make sure you file the groove in the boom so the edges are round.