Well I wanted to try this method, but I wanted a little more height so I needed to make the original M5 screws a little longer, after some research I found these on a computer hardware site:
I ordered eight of these in 20mm length, I also needed something to support the weight of me on the seat so I had some nylon spacers which I cut to 12mm in height then on to the installation, as you can see I cut the nylon spacers with a little difference i height, I wanted the front one a little higher to get the seat a few millimeters away from the "tank".
I did the same way on the rear ones, I also put an extra spacer under there to help distribute my weight, I will replace these nylon spacers with a cut and drilled peace of nylon instead.
Now the rear side with the lock was a little tricky, I decided to bend the peace that unlocks the front seat, so the the key now only operates the rear seat.
But thats not a problem, since there will be a gap when you remove the rear seat, you can just put your hand under there and press the lock. But that will not work if you have the seat in low position, so I have also put in a wire that hangs out under the bike, which you pull to release the front seat, thats a little security problem, but no one will see the wire and no one will know what its for, so I'll take that risk. (I won't show on picture

)
I had to trim the plastic a bit since it pressed on the lock, to release the front seat you just press the locking button. Also had to remove the rubber on the plastic cover.
Original seat in high position, you can see the white nylon spacer, but I will change these to black nylon or paint them.
Original seat in low position.
Sargent seat in high position.
So, conclusion, the raise is about 13mm and I think thats the maximum that can be done, in the front the guides on the seat will interfere with the tank if you raise it more and in back the locking mechanism will be in the way.