1) In general, when should you rack to the secondary fermenter?
2) Should I wait until the krausen has completely dissolved or should go ahead and rack to the secondary after the 6 days of primary fermentation?
3) Since one of the reasons for secondary fermentation is a clearer beer, should I even be doing secondary fermentation on a Hefeweizen?
Ideally immediately after the Kräusen settles. But you can leave it as long as 2 weeks (from beginning of primary) without worrying about any possible flavours resulting in the beer. Ales can be left long than Lagers. I’ve sometimes left Ales for more than a month with no problems.
As long as it is beginning to settle, you can rack. Most of what I’ve read and experienced is that there is a chance that racking can cause a stuck fermentation if you do it too long after High Kräusen settles down. I’ve never experienced this personally even though I’ve done that quite a lot, but it’s useful to know just in case you do get bitten.
Hefeweizen should be relatively clear, too. The wheat will give you sufficient haziness, as will the sediment from the bottle.