The draft version is 195 pages long, so i put my eyes on the available classes.
There is a mystical relationship between iron and magic that few understand. When carried upon the person, iron tends to interfere with spell casting, and therefore Magic-users do not wear or carry any iron objects larger than a knife. and will often prefer even their knives made of bronze or some other non ferrous substance.
Further, during the process of spell casting, the entire body of the caster becomes charged with the spell just prior to its release. Tight clothing or worse, armor of any sort, can create an insulating effect that reflects back some of the spell energy creating a hazard for the caster. Because of this, Magic-users typically dress only in sandals and loose fitting robes and will not wear any type ol armor or helmets. When times permit. Magic-users will often prefer to wear nothing at all!
Small iron objects will cause a 10% chance of failure for each spell casting. Larger iron objects, such as a shirt of chain mail or a helmet cause a 75% chance ol failure (or a miscasting) and loss ol the spell. In addition the caster may take heat damage at the discretion of the Referee. Even greater amounts of iron on the person. such as a plate mail suite, guarantee a 100% chance of spell failure.
So there is no confusion, these restrictions do not apply to Clerics casting Clerical magic. which is a divinely granted power unconnected to iron and quite different in nature from the magic ol Magic-users. Elves, it should be noted, are able to manufacture a magical armor in which the wearer will suffer neither the chances of spell failure or heat damage indicated above.