Re: No spotter for noob...bad idea?
The thing is, if you fail on a bench attempt you'll most likely be able to control it down to your chest at a reasonable speed until the spotter is able to help you out. If you lose your grip and dump a bench rep (much more common with a suicide grip) the bar is probably going to crash down on your neck or face before the spotter has a chance to react.
I'm still baffled as to why you "can't do it any other way"--what is it that's keeping you from wrapping your thumbs around the bar? If one of my clients let his knees come in and rolled forward on his toes on every squat rep, I wouldn't accept "I can't do it any other way" as a valid excuse...I would find a way to fix it.