Magnitude vs. Skill

From MRQWiki

To impose a concrete limit on what spell magnitude a given character can achieve, interlock the spell magnitude with the caster's Runecasting skill thusly: for every 1 magnitude, 10% of Runecasting skill is required. To cast a magnitude 1 spell, the caster must have at least 10% in the appropriate Runecasting skill. To cast a magnitude 4 spell, the caster must have at least 40% in the appropriate Runecasting skill. Likewise, magnitude 6 requires 60%, 7 requires 70%, 9 requires 90% and so on.