I hunt in heavy iron. A lower recovery is often what most guys run with. I think something that is VERY IMPORTANT IS RUNNING CORRELATE. Sorry to yell, but it makes a huge difference with correlate. Not only is correlate GREAT in heavy iron but it really quiets things down there as well. I made a video of the V3i in iron, it will give you an ok idea of the sounds and pulling harder to get targets. I'll link it at the bottom. I don't get into the recovery delay really, but that is the easy part! (Note different sized coils also).
The way to go is probably a smaller coil but you will get results with the stock coil as well. A recovery delay for the stock coil in iron is what was said previously. Out here in Europe we even go lower. BUT, when running correlate you don't (apparently) have to go as low (fast recovery speed) and rather higher may be better as you are giving correlate more time to compare and correlate the frequencies (But you have to test this due to all the variables in different grounds). Do a search on setting up correlate. Also, you probably don't want to overpower (sensitivity) your detector. That can do more harm than good. In heavier iron I often drop it down. But you will know from how the detector reacts with the ground and if it falses.
Something I run in all the time that was mentioned by another poster (Cybersage) is running modulation at 2 (especially where there is lots of iron). I have thoroughly tested this and it doesn't affect deep coins (no modulation) but does quiet falsing on deep iron (in my ground - low mineralization but high iron mineralization).
Good luck and let us know how it works out for you,
Albert
[video]http://www.youtube.com/watch?v=0myj4kRMCok[/video]
[video]http://www.youtube.com/watch?v=thXVLhUqsGQ[/video]