There isn't much power grinding out there. If you are going to do it, grind that nub that hangs down in the port where the valve cover bolt is. Grind through it until it's gone. It will break through but that's ok. It doesn't need to be there.
The power is in the valve job, and both ways from there. Into the port and out to the chamber. Also, the shape of the guide is important.
Don't work the bowls until you have established the valve job with a top cut and the chamber is rough finished.