Best Upgrade System for AOS style Map

Hi I just made a new AOS style map and i want to know the best way to install an upgrade system. I basicly want to have 3 levels of each type of upgrade.

Armor
Hit Points
Move Speed
Attack Speed
Building Armor & Hit Points
Moonwell Upgrade

Ideally i would like to set up a building like a workshop and have it so anyone can walk up to it and start doing the reasearch. I fear this gona be more tricky then it seems.

Do you know anywhere i can read about setting up an upgrade system like that?

Thanks.

Well, I'm not sure, but this is how I would do it, it's probably clumsy and would get torn to shreds by someone more adept, but I think it would work: - have a building that can sell items like a goblin workshop, call these units armour upgrade, moon springs, health boon, fortified buildings, really storng legs and manic sword arm, say. Make the computer units have upgrades equivalent to those. Then set up a trigger that says
Event: "A unit sells an item (from shop)"
Condition: "<[event response] -sold item> is equal to <upgrade item-name>"
Actions: "remove <[event response] - sold item> ; Set the current research level of <desired upgrade> to <current research level of <upgrade>> +1"

Using the bundle of lumber as a base for the item also gets around the problem of needing a free inventory space to research upgrades, in the which case you could just remove the remove <[event response] - sold item>

As an aside, that would make a simple way of showing the number of upgrades researched by each player - if you made each of the lumber bundles worth 1 lumber, you could then have a leaderboard with each player's lumber, which would show how many upgrades they had researched, just a thought.

You can compress it into a single trigger with lots of if clauses, but then it's far harder to edit later on, IMO simplicity>complexity no matter what.