911 Valve Seat Grinding

[AV8TOR]

First let it be said that I am a neophyte head re-builder. My work to date includes
removing and installing valve guides, reaming valve guides, grinding valves, NOT
grinding seats. I am not able to be an understudy to one of the great Porsche 911head re-builders, so I turn to you fellow Pelicanites, for a web based discussion.

Several years ago I purchased a B&D valve grinding machine, seat grinder, and reaming kit. Recently I purchased 30, 45, and 75 degree valve seat grinding stones from Goodson.
I am rebuilding a '69 2.0L "T" motor for my 914-6 restoration.
So........
I lightly oiled the stones, and slightly lifting the seat grinder, tried to grind squeezing the grinder trigger for just a few seconds with each stone.
I am not getting satisfactory results by my estimation. You can see in the first picture the seat does not have the nice sharp edges at the 3 angles.
Perhaps my first mistake was using a good head.

What should I be doing differently?? Are the Porsche seats too soft for the ruby stones? Should I use more oil? Should I do the grinding by hand??
HELP!