Hows it going man @RickJohnson
so endmills are you #1 cost when owning a machine (as far as consumables)
if you want quality products use quality tools they will pay for themselves with the more customers you attract
I would invest time in learning about cnc bits do reading, ask questions, perform tests, and watch videos basically do everything that you can to understand the tools you buy
For your problem here I would ask
What material are you cutting?
if your cutting things like wood or aluminum you want to go no more than x4 the diameter of the tool
if your cutting things like foam or wax you can really go as long as you want in most cases
try and buy only solid carbide tooling I would stay away from HSS tools as they are material specific and when starting out you want multi purpose tools
Here are some tool manufactures that I commonly use
LMT Onsrud
Tools Today (amana tool)
Whiteside Machine Tool
Magnate Tools
CMT Tools
Vortex Tooling
All of these produce quality tools
I would also research and understand chipload and feedrates so you can make the most life of your tools
On the stepped cutting depths its all in the programming I would source out and watch youtube videos on people walking you through the process Personally I would get away from easel and start using more v-carve pro and eventually look into Fusion 360 and then if you get really serious and maybe upgrade to a larger machine look into things like Mastercam etc.
for the lifted gantry be careful on how high you go as the machine is already flexible and can get even more so the higher you go without heavy heavy modifications and at that point your better off buying a different style of machine in the mean time I think cnc4newbie sells decent z-axis upgrades
hope that helps