[Loredweller]

1. As soon as you have at least one spell (any one) of desired effect you could go to spellmaker and make one of your own. In your case you could make a spell Open 100 on Touch and could name it as you saw it fit (in fact you'd have to, since there's no automatic name generation).
2. I hope i got it right (chance or change?) So, basically probability of success depends on your skill in discipline the spell belongs to and on your attribute governing this discipline. For spells it's usually either Intellingence, Willpower or Personality. Intelligence seems to be playing certain role in casting any spell nonetheless. Then, the percentage shown by the Fatigue bar also influences the success rate greatly. Luck plays its part, too, though not so obviously - but you might notice the increase of success probability in the spells list if you had noticeable increased luck (by Alchemy or a spell, enchanted items including).
There are spells almost impossible to cast with 100% success without boosts other way than from a scroll - Summon Golden Saint on Self for 60 seconds, for example. It's meant to be so.