k few thoughts. Just for starters.
The automag and minimag are exactly the same thing. Just a different body style. With both you have a stock/classic valve with a regular bolt. On both markers you can add a level 10 bolt kit to replace stock bolt. The level 10 bolt prevents chopping of paint in the chamber. (there are many different types of bodies like the ULE(various colors) The standard feed and power feed to name a few.
With the Automag ULE RT and the tach one they are the same gun just different body style. There markers a big step up from classic valve. These markers have a reactive trigger and have no shoot down at all and uses the x-valve. Shoots very fast and you have keep up with most electros.
If you decide to get a mag classic first then later you can replace your classic valve with a x-valve and boom you have a automag RT.
Bottom line is these markers are extremely customizable! There are dozens of different set up you can go with! This is a kinda general description!
I will pm you a pic of my newest mag once i get it together next week!
Good luck on your project!