Long post follows...
I made some measurements this morning in order to answer the question "how close to the toe pick to sharpen." Some sharpeners will grind far enough to remove some of the pick, others leave a long un-sharpened length to avoid contacting the toe pick. Even the most careful sharpener won't sharpen immediately behind the toe pick because of sharpening machine geometry.
I took two different blades that I had on hand, and marked the front of the blade in 1/4 inch increments. I set them on a flat piece of wood (flat, like the ice we skate on), and tipped the blades up so that the pick just contacted the surface. I could read off how much dead space there was behind the pick. I also made photos.
I realized that toe picks "dig in" the ice when actually skating and that might affect the dead-zone, so I drilled a shallow hole in the wood to simulate the pick engaging the ice lightly.
First up were my daily Coronation Aces, now 10 years old. The rocker is still very close to the original. I traced it when new for a reference. Also I have a lot of good metal left for sharpening. (I hand sharpen, and that's much gentler than a power grinder.)
Here is a side shot of the pick area when the pick just contacts the surface. The distance back from the pick where the blade contacts the ice surface is 7/8".
When the blade rocks forward and the pick is embedded in the ice a bit, it changes the distance. In my simple experiment, I could see that I need to have a sharp edge within 5/8" of the pick. That small distance surprised me a bit...
I have a pair of Jackson Synchro blades that I once intended to use. They are unused.
The first photo shows that an length of 1-1/8" is not engaging the ice when the blade is flat on the surface...
The photo of the pick embedded in the surface a bit produces an unused length just over 3/4"...
Through this experiment, I found that the Jackson blades have a longer bit of blade not engaging the ice. It might be that the rocker is positioned rearward too, but the result is that this would be an easier blade to sharpen.
One last photo - most power sharpening equipment uses a shaped grinding wheel along the length of the blade. Because of geometry, this prevents the operator from sharpening right up to the toe pick.
My case is a little different because I use a Pro Filer hand sharpener, and I can push the stone right up to the pick. However that part of the blade has not been pre-sharpened at the factory, and it would take forever to build a hollow right behind the toe pick. Still, every time I sharpen, I run the device up to the pick. Slowly, I'm building a hollow there. Here is a shot showing my blade area behind the pick...
I'm creeping up on an edge right behind the pick, but from feel, there's about a 1/2" length that remains without a good edge. Thankfully, my measurements for Aces show that even with the pick engaged, I still have a good edge on the ice. That first 1/2" length of sharpened blade isn't needed.
One conclusion is that various blades have differences in the unused length. I would expect that with worn blades that sharpening would be required nearer to the pick. Check your own blades on a flat surface to see if your sharpener goes far enough.