Under what conditions would you tie the the clew tie down as close to the end of the boom:
Always - this maximises the efficiency of the vang as well as gets your sail in a tight as possible when blck to block (meaning the two end blocks are touching one and other)
Under what conditions would you adjust the clew outhaul out?
Generally when you need to power up in light wind, as the wind picks up, and you get overpowered, you'd tighten it up. I have heard various metrics, but I try not to have more than 10 inches max between the boom and the foot of the sail at it's widest point.
If there's any confusion there, Chris, the clew should always be tied or strapped tight to the boom - in all conditions. As Mawill said, it makes the vang work correctly and helps keep the sail shape correct.
The outhaul, in and out, is adjusted to suit the wind and sea conditions. Fuller (deeper) sail at the bottom means more power up to a point, then the air separates from the sail and defeats the purpose. You have to experiment with this and feel the changes in speed.