The only thing you need to do for PPL is apply wind to a track to get a heading. For this, wind up is easier, since it doesn't involve jiggling the wheel around.
However, there are a lot of problems which can't be solved using wind up, which you'll need to learn for CPL/ATPL/etc, or might like to know just for interest. For this reason, my instructor insisted that I learn wind down. With a bit of practicing, the jiggling around takes no time at all - and I now find wind down easier than wind up, although this is only because I use it more frequently.
Another good hint for learning to use the wind side of the whiz-wheel is to draw the whole of the wind traingle on, not just the wind mark. This helps visualise exactly what you're trying to do. Obviously once you understand things a bit better, you can stop doing this.
As with all things, though, it's alway a good idea to do whatever your instructor recommends - that way, if you have any questions, he'll be in the best position to be able to help you out.
FFF
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