I've only got practical experience of traditional wool kilts, but I have heard that those made of a viscous mix or other man-made fibres tend to loose a lot of the sharpness of the pleats when wetted and dried out.

I have always been taught that as wool is a natural material, it needs to "breathe" and should not be sprayed (sealed) with rain/stain repellant, apart from any risk of the chemicals in the spray reacting adversely over time with the natural oils in the wool.

The best rain kilt is a 16oz or heavier, as the heavier tighter weave tends to shed rather than absorb moisture. However, the lighter 11/12oz wool generally used here for 5yd kilts is a much better weight for hiking. Obviously, the best idea is to avoid getting it wet in the first place, but when hiking most people tend to pack a short rain jacket which doesn't cover the kilt and often makes the kilt wetter by shedding additional water on to it.

If you get a wool kilt wet, the best thing to do is, as soon as practical, hang it up and let it dry naturally - the pleats tend to stay sharp and any creases will come out by themselves either during the drying process or as a result of body heat the next time it is worn.

Midges are really only a problem here in July/August/early September, and its actually only the pregnant females which bite, seeking blood to feed their developing eggs. However, it's quite possible to have several thousand midges per square metre in certain areas, and although some repellants are highly effective, you are very vulnerable in a kilt!