Hi Tim. Could you include a picture of your jig? Many here might be curious. I certainly am. Sounds like it is a jig to create the camber on a grinder since you mention that it is a hollow ground edge. Besides your scrub plane, which do you like to put a crown on? Just curious.
Lots of folk like camber for one purpose or another, as opposed to just taking the corners down a bit the way Paul does. They even talk about exactly how much camber to use for each type of plane. They can bet pretty precise. Obviously crowning a good bit is required for a scrub plane. Given what a scrub plane is for, that probably does not have to be very accurate. Some like it for planes used to joint the edges of boards. That has to be somewhat more accurate I suppose if you are going to take predictable amounts of wood off the higher parts of an edge. I did that for a while and it does help edge joint, but I seem to have stopped and just use uncrowned planes for that. Maybe that is a mistake on my part. And of course, a bit of camber is nice for a smoothing plane. That is the main place I like to use it. I have a number 4 I just use for smoothing and I put a bit of camber on it, but I do it by applying more pressure on various parts of the plane while basically sharpening as Paul does. It is not very accurate I suppose, but it seems to work okay. I seems to need only a tiny bit of camber for smoothing pretty well.
I would be curious about how others use, or do not use, crowning on their planes.