A forstner bit is nice, but overkill. On mahogany, I wouldn't use a spade bit. A spur point bit or a twist drill (if sharp) would work. If you clamp a piece of plywood over where you want to drill, you should minimize chips. A forstner bit is nice, but you can burn one up if you aren't keeping it even and loading up one point. It would be a waste to ruin one. Drill a pilot hole through using a smaller bit,and use the bigger one from both sides to prevent chips.
A small square held up near the bit helps you keep things level and square. It helps to have a a second person to judge the other orientations.