A hook is totally a legit stance in my book. I'd rather drill from a shitty stance than from a suspect hook any day. At least that way you'll know when you're about to take the ride.
Creativity is the key, I drilled a bolt hanging from my nut tool last weekend. It was a wildly flexing flake, but supported enough weight where I could milk a horrible stance enough to free my hands to drill. No way I could have done it without that hook. The bolt before that one was drilled where there was no real stance. Only a left and right facing flake about five feet apart where I found I could do the splits and use my lack of flexibility to free my hands.
Sometimes, like what Bob said, you gotta go with the tap,tap,tumble method. I've spent hours trying to get a drill bit deep enough to where I could hang from it.