Yeah keep some as templates, nice and easy to cut around. With the stock precut ones being so thick, you can get super close with the scissors with no risk of cutting the stock mesh. Just makes it easier to get a good clean cut. You'll get the hang of it pretty quick.
When you go to dry burn it to burn the oils off the Mesh, just pulse at around 15 to 20w, no higher. The SS316L mesh is really thin, so will snap if you go in with a silly high wattage. Not that it matters when you have a 5ft roll to practice with