The hum from the J pickup in the PJ5 set has about 1/10th the hum of a single coil. Because one coil is for 2 strings and the other coil is for 3 strings, it does not hum cancel 100% like the 4 string design does. But the hum is only there if you listen for it. I have been making PJ5's for years and I have never had a client find it a problem in the real world.
Roger
Roger