The following is something Brian posted on PMUG
(https://groups.yahoo.com/neo/groups/PMUG/conversations/messages) in
response to a user who had trouble getting started in stetting up a
grading rule:

First of all, about the layers: You should decide before you start
grading what your sizes will be, and what layers those sizes will be
on. PatternMaker allows you to use whatever size names you like, for
instance S-M-L-XL or 6-8-10-12-14 etc. Give the layers names, and make
sure that your base pieces are on the layer for their size. When you
grade PatternMaker will put each larger size on a higher layer, and each
smaller size on a lower layer, so you would not be able to grade down
if you left the pieces on layer 0, the default. If your base size for
grading is Size 12, then you should either draw the base pieces on layer
“Size12″ or move them there just before grading, with the
Edit->Change Object command. Note that each arrow is defined for all
PatternMaker layers, even the ones you aren’t using, and the breaks and
dX and dY values don’t change even if you change the layer of the
object that the arrow is attached to.

Second, about grading tables: When you run the Edit Arrow function and
select an arrow, a table appears in a pop-up box. Note that this table
is NOT the full grading table; it is only the grading data for a single
arrow. The Edit Arrow table shows what layers contain breaks. A break
is where the grade (for that arrow) changes from what it was for
smaller sizes. For instance, if you use a 1 inch grade for sizes S-M-L
for a particular point, but the grade from L to XL is 2 inches, then
there would be a break at size (layer) L. You only enter dX and dY
values at breaks, because the same numbers are reused for each larger
size step until there is another break. (Arrows always have a break at
layer 0, since that’s where the values start from.)

The default name for each arrow when you create it is “Arrow”. Be sure
to give each arrow a descriptive name, or it will be very difficult to
use the grading table file later.

To continue about grading tables: We recommend you use the pop-up table
when first creating an arrow, or to make individual adjustments, but
not for further editing. Work in the text file to make most edits or to
create a large number of arrows at a time. When you create a table
with the “Save Table” command, the resulting table is in text format and
can be edited with any text editor. We don’t document the format, but
it’s very simple. Here’s an example:

Patternmaker Grading Table