Welcome to the ALR, Andy. I have not seen this kit other than on David's web site. From the pictures, it looks like it might be easier than the GPR kit, as the inletting is probably better. I have met Dave Price at Dixon's Muzzloading Gunbuilders' Fair. He is easy to talk to and always willing to help other builders. I would email or call Dave and talk to him about your experience, and whether this kit is right for you. I believe you'll get an honest answer. I also know that he would be willing to talk you through any problems you might have with the kit.
You may even get an answer from Dave right here on the forum, or a message through the forum mail, as Dave is a member here.
I have no business interest in David Price Flintlocks, nor can I say that He and I are close friends. I just based my answer on having talked to him a few times at Dixon's and his postings on this forum.
Good luck with your build. Whatever you decide, we always like to see pictures of other peoples' progress as they build. Don't hesitate to ask questions here. There are some of the friendliest and most helpful builders on this site.
-Joe