I have made lots of terrain using the Terrain Maker system. For my hill hexes I have 2 elevation sizes that I currently use. For my gentle sloping hills, I actually use 1/2 inch hexes cut in the same fashion as the 1 inch hills described in the instructions.
Whether I use the 1 inch or 1/2 inch slopes, I do glue these to the 1/2 inch base hexes. The reasons I do this is two fold. 1. It is sturdier and less likely for the slope to shift during play. 2. I blend the base of the slope in with the actual slope using Durham Water Putty. This allows for a smooth transition with no visible gaps in the slope hex.
For the hilltop hexes, I have done them both ways - For my 1 inch hilltops I have glued the hilltop to the base. For the 1/2 inch hilltops which is what I mostly use, I just use the 1 inch hill hex by itself without any base hex underneath. Alternatively, you could use 2 1/2 inch hexes here as well - the one underneath being a plain unpainted styrofoam hex
used as a spacer for the 1/2 inch hex above it.
The 1/4 inch hexes are usually used to make the rivers, streams, and lakes. I don't use these in making my hills and slopes but do everything using the 1/2 ground base.
I also use a floral cutter to cut my styrofoam as my luck with the coping saw method was pretty bad.
I hope this helps you a bit.Pete - Binpicker, Out!