Some good advice here, watch some U tube videos, get a book, buy "LOTS" of cutter heads, practice on scrape wood, etc. Forget borrowing peoples tools, buy your own tools, your not talking huge dollars here as the cutter handles are not hand crafted works of art from Germany. Purchase several cutter handles so you can change cutters without actually taking the cutters out of the tool handle. Start off recutting some existing checkering patterns on old guns that you can afford mistakes on. This will give you experience on the feel of the tool and cutters.
I haven't needed to buy stuff in many years as I don't do a lot of it and I have lots of different cutter configurations and sizes, but I used to buy directly from Dem-Bart. I would just call them and place the order. You got good advice and what you wanted without pi$$ing around with a computer, or some a$$hole at a retail store that knows nothing about checkering tools.
It is a great hobby to get into, very rewarding, I have been doing it for over 30 years. Does help when you have young eyes as now I have to use the magnifying lens with light which I never used to.