I don't believe that there is any difference between the different types of valley. It's all anecdotal evidence. It's like asking someone to flip each of a penny, nickel, dime, quarter, and half-dollar ten times each. When the penny comes up heads 8 times they says "pennies are more likely to come up heads". This just isn't supported. Trying to make a statement like this that has any truth in it is very difficult, as anyone who has studied statistics knows.

One day when using this method to farm, I found three medals out of one valley during the day, and they were all the same kind. I could easily conclude that that valley type and level is more likely drop that kind of medal. I came here and looked at this guide again, and that valley type was supposed to drop a different kind of medal, and that kind of medal was supposed to drop most often in a different kind of valley.

The method of attack versus cav is also slightly wrong, as I've posted elsewhere in this thread.

Other than those two small problems, this guide is perfect. If I could rep you more or give you more stars I would.