Welcome to the addiction Rambaits!
The Essentials kit is nice in that it will allow you to get started without a lot of mixing...helps shorten the learning curve a bit, especially with the two molds you have coming. Personally I would find a color wheel in a local hobby or craft store. A wheel will show you potential color you can whip up using colors you have, plus it can show you what other colors you'll want to acquire to expand your horizons color-wise, and you will find that you'll want to expand that.
You'll find that glitters either compliment a plastic color or contrast with it so expanding some glitter colors will come along too. I tend to favor working with smaller baits and like using the .008 or .015 sizes of flake while others who work more with baits in the sizes you've chosen might prefer even the .040 size or will blend the .015 and .040.
The absolute MUST have that does not come with the kit you have purchased is the digital, probe type of thermometer that Do-It sells in the plastics area of the catalog or on-line store. You need to learn to live by its temperature readings. Another must have that is free is a notebook and pencil to record what you are doing step by step to get to a finished bait or certain color.
Perhaps the best I can offer is also free and is to go into all of the plastics forums that deal with the actual creating [cooking] of the plastic and go back several pages a in each forum and read, read, read. Of course there are lots of seasoned people here who will readily help out if you have questions or get into a snag so feel free to stay in touch here.
Again, welcome aboard!