Here's my 2 cents.
There are some nice prop articles in the Model Aviation Archives so I recommend to go pick them up.
There are all sorts of strange prop comments you hear about pitch etc. It is really confusing to say the least. I think if air was solid like a piece of wood, then maybe there would be some critical aspects to non-helical pitch.
However I think the plane is feeling a thrust given by a weighted average of pitch along the diameter. Ignoring the tips of the prop where things can get pretty complicated due to vortices, the total thrust is the sum of the air being accelerated by the prop. One inch of prop at a radius of 5 inches moves a lot more air than 1 inch of prop nearer the hub.
So when someone tells me they are pitching the tips less than the nearer the hub, I think they are saying the engine/plane really wants a prop with less total pitch. I don't think there is anything magic going on with the air in the last couple of inches which somehow pulls the plane thru that corner you just hammered!
However it is easier to repitch the tips than the (w)hole blade.
edited to fix my spelling mistake, since we are now taking notice!!