Welcome to Router Forums. There is a lot of talent here and at least one of us should be able to help you even more than I can. They will likely respond soon.
If I understand your problem correctly, you can't use these inlay kits if the pattern has any sharp corners. The bit and guide diameters limit how tight a corner that your inlay can have. A rounded pattern like a teddy bear will inlay well because there are no sharp corners. Inlays with sharp corners can be done, but manually using a razor knife and chisels with a lot of practice.
If you can post some pictures of your problem it may help us better understand what you are talking about. (You can only post photos from within your computer until you have posted here a number of times - no URLs, for newbies. It's an anti SPAM thing).
Also, please take the time to fill out your profile (click on "edit Profile" at the top right of your screen. Knowing your name and roughly where you live, what tools you have, and how much woodworking experience you have can make a big difference in how we respond to your questions.
Again, welcome to Router Forums and our sawdust pile.
Central North Carolina
Last edited by CharleyL; 11-14-2017 at 10:01 PM.