That's one way to do it. Here is another.
What you are doing is finding the Max OAL for that particular bullet. This technique is of course "Bullet" specific and must be repeated any time you change bullets.
This is Max OAL with the bullet touching the lands. IMO you do not want to load this long. Touching the lands will cause an increase in pressure. As Nosler states in the above link, reduce Max OAL by .015-.030 to start.
Remember the longer your OAL the Higher the pressure, so if you are starting out at say .030 off the lands, increasing OAL to .015 off the lands will also increase pressure. It's better to start long and go short then to start short and go longer.