Torges seat - where to put the holes?

[SOS]

I've got my seat cut out and am going to use (I think) the prussik rope version.  How far from do you find is best to put the holes for the rope?  Also, has anyone used a couple of nails or screws on the tree side to better bite into the bark to keep it from slipping?  Any other lessons learned?  Steve

[redfish]

I put the holes about half way from the deepest part of the trunk radius to the front of the seat so that it would balance.