Yes indeed, wands of sleep paralyzation are very useful when you are fighting low level (but still dangerous) enemies.

What I would like to know is where exactly can you get minor globe of invunerbilty?

I played all the BG1 + TotSC with the multiclassed MAGE/CLERIC ant it was fine. I think the battles are not so easy as with meelee char. but are definitely more funny. I dont like the hack'n'slash type of play. So i think its possible to play BG1 + BG2 with the MAGE, just try and you find out your self.

I've played through, Bg Tosc and IWD, HoW without using a single mage or even a multiclass one, or a bard. I've done just fine. between the potions, wand, and necklace of missles, wand of heavens, and ring of energy i've managed to cover everything that a mage can do. It left more room for tank characters (5,all but my thief) I just plow through baddies most of my battles don't last long enough to even use a mage and some of the better spells, i started this all on a bet and i like playing without a dominate spellcaster. I may seem a little too hack and slash for some, but i enjoy it, my cleric/ranger has enough spells to keep it from being like that.

(bg2 though, i wouldn't advise without a mage or two)