I have been experimenting with off boom sheeting on my Streaker. The reasoning being at Burghfield it can be light and very unstable winds. I felt that off boom sheeting would give me better control and allow comfortable sitting on the thwart. I have done some testing and one race. The first hour of the race was light and I think I was competitive, certainly in the mix with much newer plastic boats. Towards the end of the race the wind increased and I lost out. At ball park about 5-10 knots it is difficult to accurately sheet the boom to the correct position.
I then tested with a snatch block down on the sole of the cockpit. Sounds complex but very easy to open and close the snatch block with one hand and switch modes
This was fine but the boom appears to sag off a little because the block is so far from the boom. I tested with this and more just off boom sheeting. Luckily the day was fluctuating between 5 and 10 knots long gusts nearer 15. There was a certain point where with off boom sheeting it was easy to over-sheet, particularly if wind dropped from say 15 to 10. Also if you have the stopper knot set for using the block but gybe with off boom you can whack the boom onto the shroud.
I then put a small block back on the thwart but kept the ratchet block on the boom. This appears to work. Essentially it is the standard set up but the smaller block makes sitting on the thwart and switching from off boom to off thwart easier.
The ratchet block is quite a bit forward as I have a long tiller extension. There is also some mainsheet calibration on the boom