Thanks Craig.

Zoli tells me that his software still needs a lot of improvement but I am certain he will get there.
He now has a nice CNC pyrography set-up and is making excellent progress with his work. This thread relates
http://hobbycncart.com/forum/46-234-1 so it may be worth checking back there, from time to time (for future software updates), as more is learnt about the process.
I did convert a G-ray generated tool-path for use with my laser, mainly as a 'proof of concept'. The initial test results were not outstanding (lots more practice on my part required) but I think it shows the possibilities of using variable feed-rate. (I adjusted my laser power output a couple of times during the run which perhaps spoiled the result).
(For those looking for a scientific explanation - Newton described the ‘time-lag’ between action and re-action when formulating his third law of motion. This law does not actually apply to the laser beam itself but it does apply to the effect caused by the beam and I like to think of it as ‘latency’.
Wood, like all materials, has ‘latency’ so slowly creating a heat spot on the surface of a piece of wood produces a greater shade of burn than quickly creating exactly the same calorific value of heat spot – likewise, the speed at which a heat source is moved over the surface of a piece of wood will determine the shade of burn).
Tweakie.