Title makes the best hanger for wood rafters. If you have a basement or block wall at your disposal (I live in Florida). You can get the great wall mount from Title. It might work with wood to, at least they say it will. Just make sure you buy a spring too. I'm a heavyweigh hitter and I have had a 100lb bag up for a year and a couple of months, but am about to buy a 150 which I'm sure will work with this device.
TITLE Deluxe Heavy-Duty Wallmount Hanger from Title Boxing