The way I read it, with Rune Magic you no longer use the rules for making Enchanted Items, you store a Thaumaturgy Spell - one that you actually have to perform mechanically, risk of Backlash and all - in the rune, for later, one-time use.
Normal crafting is actually pretty darned easy to hit effect strengths of 7-8 with a single slot and adding slots for Strength is pretty weak at that point, but you can never go past 10 (unless the skill cap i raised). You really only need one skill - Lore.
Rune Magic will depend just as much on your Discipline, and somewhat on Conviction, as you need to finish the spell in as few exchanges as possible since every exchange "costs" an item slot. It requires a higher Skill point investment, for comparable (or weaker) single-slot items, in exchange for more powerful multi-slot items.