I'm trying to use the shape "circular sector" pgfman301a, p.706.
I find no way to change length of axes (should be variable dependent of circle dimension).
why "minimum size" doesn't work?
%minimum size = 10cm,%has no effect?
Kpym has already told you what I was going to tell you about minimum size. Other than that you need to use an appropriate anchor and only know how big the node will be after you have drawn it, so you can draw the grid below it afterwards on the background layer.