Here is info I pulled up from the facts and formula guide:
http://strategy.diabloii.net/news.php?id=551
The FHR breakpoints are (assuming no spears/staves): 0, 7, 15, 27, 48, 86, 200
Let's say you have 15 FHR on your gear. You need to have 12 more to reach the 27 breakpoint. If you have any less, it won't make you recover any faster. Therefore, having something like 100 fhr on your gear is the same as having 86 fhr on your gear. If you can't reach a breakpoint, then don't sacrifice gear to get "partially faster" because it won't do anything.
That said, you should really try to reach the 86 breakpoint if you want to duel.