Steve,
The way I look at iron mask is the way it sounds as the more iron mask you use the more it covers up any coin that is close to iron. With less iron mask it will not cover up so much and you will hear the coins beside iron. Also in the quick start mode it is using a lot of iron mask and you may not even hear the coin beside a iron object so I run with a -8 iron mask unless it is very trashy than I will go to one of my patterns and use.
If you want try and lay a coin with in a inch of a nail and see what the difference is in quick start and - 8 iron mask. Chances are you will find it hard to get the coin in quick start and in -8 iron mask it will not be too much of a problem.
Rick
