I did something similar with an Xtreme flocked sill brush recently, only I removed both bottom rows and cut the bottom edge of the brush stock off with a jigsaw mounted in a workmate. It left me with a great everyday brush and is really good on leaded work. It’s a great scrubber on residential work, and as it has fewer bristles than say an ultimate, it doesn’t hang on to so much dirt and makes rinsing easier.
I wish Gardiner’s would put either the flocked Xtreme back into production or a DuPont TaperTec version.