I use the same grading conventions that the Acaeum uses and they are all explained with some detail there. ( it can be found from the acaeum home page under the "front desk" section.)

NM-VF-FN-VG-GD-FA

This covers the bases pretty well, but when I am listing items, I further divide them into in-between grades if necessary (such as VG/FN or VF/NM).

I feel that price stickers detract only a minor amount from items condition - if at all.  That is, unless they are very large, unattractive or there are many of them.  Further, most price stickers/glue residue can be successfully removed with some care and proper techniques (there is an old thread on this and I will see if I can find it and "bump" it to the top of the list).

Personally, I'd leave the shrink alone - there must be some way to "halt" the warping process though . . . I imagine constant pressure in the early stages must help somwhat ????  Keep in mind, that the grade will be affected by warped shrink - if a module is permanently "Bent", then the overall grade will be less.