For those centerpulls, I replaced my pads with vbrake pads and it really improved. I found it really helped with the pads hitting the rim squarely. You may not need them if you're sticking with 27", but I found the 750 weinmann on the back simply useless before swapping pads. The reach is so far when converted to 700c, and combined with how flexy the brake arms are...
I'm also experimenting with koolstops v brake pads that are meant for ebikes and marketed as being up to the task of heavier bikes at faster speeds. Since I'm going to use the super course for touring I thought it would be perfect.