I say, hold the hook however you feel comfortable. So long as you're able to manipulate the hook and yarn in a correct manner (as in pulling up loops and inserting hooks...) then go for it! I hold it like a pencil, simply because i've had surgery on my wrist which causes it to ache if I hold it like a knife. It's like knitting. You have to find whats comfortable for you.
Your swatches look good! Sometimes, a pattern will request that you only work in the back loop. It creates an interesting ribbing effect, but isn't always as strong.
Are you practicing your singles, half doubles, doubles and trebles? If you know those, you can do ANYTHING! :D