This is a bit late as I don't get around the net much these days.

Interesting that I've not heard of you or your group in Singapore. Are you interested in proper training? Even if you want to come down and check out diff types of armour. Find us at www.phemas.com.

That is, unless you are already in Greg's class and I just haven't met you yet. :P

Chris they're from sgsparring.

One way to keep cool is to wet the training clothes with water, especially the cap under the helmet but I wet my viking wool tunic that I wear over my SCA armour before training or for tournaments when I feel it's a bit hot. Seems a bit silly to do at first but it helps a lot. Even hot water drying out cools the body due to energy drain from transformation between one medium to another of the water. Another old Marine trick actually, but a scientific one also.
And don't use wool for tunics in really hot climate even if they look nice, try linen or similar airy fabrics. For me it's fine in wintertime but a bother in summer, and our summers are still not all that hot.

Another trick is to make air holes in the armour. Check out images of some old club tourney breastplates, they were sometimes perforated with holes like a swiss cheese.