http://www.twostrokeperformance.com.au/#!important-info
The outside edge is your minimum clearance, which is what most refer to when they say their squish. Depending on how the rest of the head is cut in relation to the piston dome it may stay the same clearance across the band, or may open up some more as it does stock. The main thing to remember when adjusting the squish is to take into account that any changes also effect the trapped volume and thus the compression.