Re: Topping Lift
luck: the topping lift is used to add a little fullness to the sail when sailing in extremely light air. The boom weight will pull flatten the sail in the leech (like pulling the vang very hard). The topping lift is used to counteract that.
Most of the time I leave my topping lift looser than the main sail's leech, but tight enough to keep the boom off of the dodger when the sail is lowered. This means it basically doesn't need to be touched. However in light air I will use it to adjust sail shape.
If your main sail has a lot of roach then you may need to loosen the topping lift even more to prevent the sail battens from hanging up on the topping lift during tacks.
My topping lift is a fixed piece of 1/8" amsteel with an eye splice at each end. The lower eye splice goes around a small block, and 1/4" line goes from the boom, up to that block, and back to the boom and forward to a cleat. Amsteel is very soft on the sail leech (so chafing isn't a problem) and this setup is inexpensive, light weight, and easy to adjust.
boats that I sail on regularly: Pearson 28-2, Rondar 505, Yankee 30, Blanchard Junior