I also use wooden slats that were purchased at Lowe's. I think now I'm working with a 3/8" slat - bought 1/4", 3/8" and 1/2" to try originally.
I roll my dough when it is still warm (right out of the mixer) between two sheets of waxed paper and chill in sheets. When it is time to cut, I peel back one sheet then gently replace it and flip the dough over. Peel back the other side and cut right away (on the waxed paper) while the dough is still firm/chilled. No need for additional flour at all ( not even on the cutter most of the time) and chilled cookies hold their shape so nicely. I like a little spread on most of my shapes (I like the legs on the dogs a little thicker, etc. and my work is a little more whimsical, I guess), but if I want them to really hold shape I stick them in the freezer for a few minutes until they are really firm. FWIW, I use the NFSC w/ 6 C flour and 1T baking powder.
Baking on parchment and using baking sheets with no sides (flat) helps the air circulate evenly and helps eliminate the uneven cooking. If you find it is one side of your oven (or front/back), you could rotate your sheets 1/2 way through cooking.