I can't help you with your decision on using Dutch Buckles or Whoppie Hooks. I think that's a personal decision. I have Dutch Buckles, but have been thinking of switching to Whoopie Hooks after watching Sgt Rock's video on them. The idea of keeping my wet whoopie slings away from my dry hammock is appealing to me.
That being said, with either setup, you don't need Dutch Clips. They just make it easier and faster to set up your tree straps. You can just slide the working end of your tree strap through the loop on the standing end of your tree strap (where you would clip the Dutch Clip). Alternatively, you can use a climbing carabiner. Dejoha has a great picture of it on page 85 of his book