engraving glass

[Marc Beaupre]

I know this topic has been beaten like a dead horse but would someone please give me some advise?
I am trying to engrave this photo on glass using corel draw X5, 60watt jamieson laser, lasercut 5.3.
The image comes out very sharp with little detail or very detailed but little contrast. Playing with contrast
and gamma has been random and I think my frustration is in this randomness.

Thanks Marc