First of all, TimTheEnchanter isn't very helpful in terms of lag and enchanting as a quality in the server. Second of all, you need to go to the essentials config file and do the following.
1) Go to the same configuration file you used to create the kits
2) Find the configuration option about "unsafe enchantment" you should be able to find it near the grief prevention options in the file
3) Make sure that unsafe enchantments are
allowed, all this will do is allow enchainments over what is listed with the books. This does not harm your server, nor does it create lag for your players.
I hope I could be helpful to you and I wish you success with your server.
Also maybe I could help you by aiding your server with one of my 3D banners, here is an example from a while ago. Thanks for reading. Contact me if you have questions