Using previous GFs as dimensions
Straw already said that there are six dimensions in his(?) gun, one for decay, and one for each of the enemy's last five visited GFs.
I'm just curious if they're being treated independently. A sequence like 0, 0.2, 0.4, 0.6, 0.8 actually might be quite close to 0.2, 0.4, 0.6, 0.8, 1.0, but if they're all treated independently, your classification won't see it that way.
If one wanted to make the ones you mention be treated similar, the way to do it would be to make the dimensions either:
GF[i], (GF[i] - GF[i-1]), (GF[i-1] - GF[i-2]), (GF[i-2] - GF[i-3]), (GF[i-3] - GF[i-4])
GF[i], (GF[i] - GF[i-1]), (GF[i] - GF[i-2]), (GF[i] - GF[i-3]), (GF[i] - GF[i-4])
(where index 'i' is the most recent wave, 'i-1' is the second most recent wave, etc)
Of course, whether that would give better results than all independantly I have no idea about... and which of those ways of making it relative would be better I'm not sure about either.