We also had the halyard eat up the air blocks too quickly. Went over to the Karver kbo2 which was great, lasted longer but split in the end. Have had a Harken T2 for a while, which I am very happy with, runs well, spliced it directly to the blockline. Since I don't believe it will hold forever, I have a Karver KBO4 ready to replace it.
I put a couple of layers of duct tape on the mast to protect it from the block. Bright green, contrasts nicely so it's easier to inspect the block without flipping the boat, and ID the boat from a distance...