I use 4 inch Spiral Sewn for Greaseless compounds, some use Sisal but I moved away from them some time ago
On Emory and SS polishing compounds I still stay on the Spiral Sewn after that for the rest of the polishing compounds I use the 4 in Loose Cotton buffs...
As you get used to the machine and your compounds you might choose other systems...
The 4 inch gets me into where I want buffing spine to edge and keeps the surface speed down...