Is harder than most woods. A rotozip is hard to control. For a professional looking job control is essential. A template (wood) with a cutout limiting the cut size is the way to go. A custom bracket - also made of plywood to hold the template where you want it completes the prep. My philosophy is: this is a hobby. Taking the time to do it right is very satisfying. When you consider how many working hours it takes to get that post tax $100 per hour the pro will charge it is time well spent.