I'm not sure what your pattern calls for as far as colors go but I personally don't like the white and yellow in there. They will create a striping effect when you put the quilt together. But that may be what your pattern is calling for? I'm working on a bargello right now as well. My pattern calls for 20 different fabrics from 2 coordinating color groups varied from light to dark. I would have gone with blue and green because I think they're the easiest to put together and have look good in a graduated color scheme but this is for my mom and she doesn't like green so I went with pink and purple (which I personally like a lot, I just don't find it as easy to set up like it's supposed to). I agonized a couple days over the placement of fabrics and over a couple that I ended up not feeling like they went well. One thing that helped me a lot as far as value goes, I took a picture of the fabrics laid out together in black and white. It's way easier to see which color is darker or lighter when they're all in grey.
Here's a picture of one of my strip sets. I'm not 100% happy with it but I'm hoping once I get the quilt started the fabrics will blend together better than I think they do now.
Good luck on your quilt and I'll be looking for pictures of a finished product!