750 vs 850 pressure plate

I'm converting my 750 4 plate clutch to a 5 plate. Based on the stack height it looks like about .10 inches needs to come off the thickness of the pressure plate. I plan to sneak up on it with a couple of tries.
Does all the thickness come off the main body of the plate or can some come off the raised contact area? Seems like taking that much off the body will leave it mighty thin.

my measurements show it to be .120. and I take all of it off the friction face. what clutch plates are you planning to use? as this is a good time to set the overall stack height. I DO NOT like the barnett clutch plates. I prefer the sureflex but you will need to do more work to use 5 of them.

I'm using Barnett plates. When measuring the stack height exactly where do you measure on the pressure plate? Just go to the highest point?

You measure the stack to the face that the diaphragm spring rides up against.

I go for a full stack with my sureflex plates.
In otherwords, if you put the plates in, the the end pressure plate, and then the diaphram spring, you can just nicely get the wills ring into the groove, as long as you have the spring correctly set on the spring compressor.
Cant remenber how many plates that means, but the assembly should almost fill the basket.
Stu