Mark,

If you already have a small line running through your blocks add one or two blocks so you have a bigger purchase. You can setup the main sheet blocks as John Alani does so you don't have to worry of sheeting in too hard (optimum point is block to block).

I have a 1:8 on the main with a 4 mm line running through the blocks.

For the spin, we have 2 auto ratchets instead of one (which is not really a problem in light air either).
This setup is feasable for me on the main and Kathleen on the spin. Ofcourse we divide the job and Kathleen has 2 hands free to sheet in the spin. (And she's starting doing the main upwind now ... :-) )

Finally when I sail one up I try to steer on the downwind and not to sheet, which makes it a lot lighter...