I bought a kit - my first - from my LQS. It was from a national designer and was kitted by the designer and sold to the LQS. That was five years ago and I'm still working on the top. The kits (one for each block) were skimpy on material. I had the same problem you've got and finding extra material has been a PITA. I just put the kit away until I can afford enough Prozac to let me finish it.
I have been sewing for almost 60 years and this quilt is the only kit I've bought. It is also the last kit I'll buy.