YES use the 40mm White stone it is quite good, NEVER use the 20mm grit stone unless you have nothing better.
The picture is not sharp enough to be 100% certain, but having ink left on those wing tops means that you have probably over rotated them at some point creating a second bevel, which is very easy to do with the course grit of a standard grinding wheel.
Basically that wing is your main cutting edge, if you can see it, it isn't sharp! Switch to the white stone, take note of the start stop position of the handle swing and work your edge back until it is completely clean and see how it cuts! Then try to repeat that on every sharpening.