View attachment 615618 This is an example of what I started milling posts from smaller diameter logs several years ago. We mostly start where we are, and have experience teach us. I still use the combo pictured for edging or cutting from inside a larger slab milled with the ms-460 in my avatar or the 661 that sings a great tune in the cut with correct feed rate. Check or have checked the pressure/vacuum in your power head to be sure it's in good order, clean the air filter, check the fuel filter. Inexpensive care for a tool that has a habit of being expensive to rebuild or replace. Match the chain to the power and length of the bar. The combo in my avatar is sixty inch bar with skip chisel chain pulled around it. Half as many cutters reduced the power required but still slowed the feed rate to keep the power head singing rather than bogging down in the cut.
A few days milling will teach you more about what works best for you, til you learn more! Reading milling 101 is worth the effort
Stay safe and enjoy y'all