I typically dry hop 6-7 days before bottling/kegging a batch that's going to get dry hopped. I've also used 1-3 ounces of whole hops in batches so far (~6 gallons into kegs). At this point, I'm liking what I get from the 3oz split between EKG and Fuggles in my English IPA's... I have a batch that got 2oz total for the dry hops and am seriously thinking about adding another ounce to the second 3 gallon keg (in a bag of course) when it goes into the brew fridge. You'll get some flavor addition from the dry hopping too, which makes it even better IMO.
While I'm not an IBU freak (highest IBU batch I've brewed to date is just over 53), I really do enjoy the dry hopped English IPA's that I'm brewing.
BTW, 1oz for 5 days will be more subtle than 7 days, or 2oz...
Do what I've been doing... Dry hop it with one amount, and time frame, taste it and then modify it for the next time you brew something that will get dry hopped. Keep experimenting with amounts and times until you hit upon the combination that works best for you, and what you're brewing.