It definitely helps if your miter saw is big enough to cut through a 4×4. Our miter saw wasn’t big enough to cut through a 4×4 with one cut so we had to cut into it half way then flip it over and cut the other side to cut through all the way. You can mark all around the 4×4 to help get a clean cut. Toni just eyeballed it and actually got the cuts pretty close. We recorded a video of the process if this sounds confusing.