[caldrail]

Look at the list of your texture slots in load.ini. Each is in order and represents a greyscale colour. so...

LowLand0 = colour 0
LowLand1 = colour 1
Lowland 2 = colour 2

etc etc

Woods = colour 26

Get your 'selection' either from your existing map_T or from map_H

Does that make painting any easier?