Hey Fez,
Sorry for the bombardment of questions, but I find HF to be an intriguing aspect of handicapping.
How often do you change/update your HF ratings?
Do you need to see multi-season trends to make a change?
Does how good a team is in general terms affect their HF rating? IE, does a team have less of a HF advantage when they're really bad compared to a year when they might be good? Or by that extension a major injury at QB taking a good team to a really bad team?
Take IND's HF at 3.5 which implies .5 better than an 'average' HF advantage. If Luck got injured, would we see the HF advantage drop to 3 (average)? Would the Saints without Brees at QB still have a 4.25 HF advantage?
Without really examining it, I'd like to argue that in general, you have to be an average to above average team in order to take advantage of any HF advantage.
There doesn't seem to be a lot of talk or discussion about HF advantage, but it can make a big difference.
For the record, I've been taking your HF ratings, and using Football Outsiders Home/Road Stats to adjust them slightly throughout the season.
Maybe RJ can bring up HF advantage as a discussion point in one of his Dream Pods. I think it'd make for an insightful and enlightening discussion.