Not snatch blocks!
For my asymetrical, I used 60mm VF composite Lewmar rblocks that I attached with snap shackle adapters. I attached these blocks aft of the primary winches on the toe rail. You should not use snatch blocks for this type application, as the sheeting angle is far too severe for a snatch block. I do use snatch blocks that are attached mid beam that will allow a narrower sheeting angle if you are sailing closer to the wind.
