It's great you're doing this! Congratulations.
I'm puzzled as to why you prefer Power Grips. I found them hard to get into and somewhat hard to get out of, and not suitable for me in heavy traffic where I had to stop so often. My favorite system is Shimano SPD's, but unless you want to carry extra shoes or make do with walkable but not-so-great-for-walking (or working!) SPD equipped shoes, they're not as practical as clips and straps.
Why can't you still use clips and straps?