pto speed

My tachometer has a note saying "PTO-1-540rpm x 1000 rpm." Does this mean that when the engine rpms are 1000 the PTO shaft is turning 540 rpm? I don't want to overspeed my brush hog (which is an obscure, apparently obsolete model with no manual or online info available) but although it does turn...

What is the best speed to use shredding knee-high grass with MX6 rotary cutter and what is the best gear for the tractor?

The pto shaft is interchangeble, is there some way i can add a spacer and get the 540 pto rpm at 1100 engine rpm. I know some tractors have the switchable pto speed lever which makes this possible,