Here's a twist I don't think I've seen before: My aim point is mid-way between Grade 2 and Grade 3 instead of the traditional Grade 2.
I defined this by setting my upper and lower control limits by picking a negative that printed properly on Grade 2 with a moderate amount of burning, and a negative that printed well on Grade 3 with a little dodging. Naturally, I want to have my aim be in the middle.
The flexibility of the ideas behind the system allows us to do things like this. I standardize on a flatter-than-normal negative by calibrating to a grade 3 paper, when I use the Zone System (not all that often any more). I started doing this simply due to the slim selection of graded materials. There are only a few grades available now. I like standardizing on grade 3 because with the graded paper I use (Emaks), it gives me the choice of using my standard grade 3, one grade below standard, and one grade above. And it also gives me negatives that will print just fine on VC paper, with plenty of room to raise contrast or lower it.
"Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."