You can't have multiple instances of the same spell(at different levels) on the amulet. The way the rule reads, it essentially replaces the lower level spell and the lower level spell is a requirement in order to get the higher level one.
Question at 13:00 ish. Page 25 of rules. "Ranked skills must be acquired in order and each higher skill replaces the previous ranked skill (cannot have the same skill w/ diff ranks at same time.)
Thanks for sharing. Great explanation on things. I like your suggestion of turning the dial. Questions - I think it is like this, but not 100% sure. The wizard's skill cards must (can only be) on the Spell Amulet. Meaning, none of them are in effect all the time (setting below the character board, etc) and for a skill (spell) to be in effect the Ready Marker must be pointing to it. Which may mean, a wizard can only have a max of 4 skill cards in play. - Can the wizard have more than 6 mana? Meaning, the 6 on the Wizard's character board is not just the starting mana, but also the mana limit.
For question 1, correct. All skill cards have to be placed on the spell amulet somewhere, meaning you only ever have 4 skills/spells at one time. For question 2, as you level up from Level 3 - 5, your mana limit will increase. So if your starting limit is 6, once you reach level 5, your limit will be 9 mana.
I think its ok, the target hero, who posses the frost armor, need discard this for the skill use, but remember every time you use a skill in the dial its rotate, so you need to spend least 5 mana to give 2 frost armor in same turn. Without a dial the wizard would be too much op