Stats on equipment are random, but generally speaking you should get enough resistance between Magic Barrier and equipment bonuses. If you run into problems, you could also start using Spell Shield (which is particularly helpful with poison damage); I maxed this skill, as well as Aura of Guarding, with purchased spell books.
The only charm I used in my first game was a gold strength charm. It allowed me to equip the two handed Bastard Sword dropped by the knight by Stormfist Castle a couple levels earlier than I would have been able to otherwise. If you need the strength to meet an equipment requirement, then go ahead. If you don't really need a bonus, but that is the gold charm you have available, then it still wouldn't be a bad idea to use it, as long as you leave enough open charm slots that you can adapt to whatever your requirements are when you get access to more gold charms.
