[Trigger] Spells in ORPG with save/load

[P3in]

Hello guys, i've started to continue Tr1inity ORPG map for who knows it. It's an orpg map with 4 jobs, save/load system, many bosses to fight etc. Each new job, has a spellbook with the old job spells, for example job 2 can learn 4 new skills and also has a spellbook with job 1 spells; job 3 can learn 4 new skills and alos has a spellbook with job 1 and 2 spells, etc. When i make the spells for the spellbooks, i want to make them upgradeable, even if at job 3 you will also have a job 1 spell, i want it to be upgraded to the level of a job 3.
My question is, how would it be better for spells to be made, have 1 spell that upgrades with each job? (the spell having 4 levels, if you have job 2, set the level of spell from job 1 to level of job 2 and so on) Or shall every spell from the jobs spellbooks to be unique? Like instead of making 4 levels of 1 spell, make 1 spell for each level , so a total of 4 spells to be able to upgrade one. How is it better when you can have multiple heroes in the same time?
Also, when triggering a spell, would it be better if it's the 1 spell with 4 level upgrades, to make all effects of the upgrade in a single trigger and make it based of the level of the skill, or make separate triggers for each level of the skill?(in order to avoid malfunction when more heroes of the same class and job are in the game)
Thanks !
Below it's an example of "trigger" with each level of the spell doing something else.

• Aura of Greed Spellbook Copy
  • Events
    • Unit - A unit Dies
  • Conditions
  • Actions
    • If (All Conditions are True) then do (Then Actions) else do (Else Actions)
      • If - Conditions
        • (Level of Aura of Greed Merchant Job 2 for (Killing unit)) Equal to 1
        • (Unit-type of (Killing unit)) Equal to |c00FFD700[Merchant] - |c008A2BE2[Job 1]|r
      • Then - Actions
        • Player - Add 15 to (Owner of (Killing unit)) Current gold
        • Floating Text - Create floating text that reads +15 gold above (Killing unit) with Z offset 0.00, using font size 10.00, color (100.00%, 100.00%, 0.00%), and 0.00% transparency
        • Floating Text - Change (Last created floating text): Disable permanence
        • Floating Text - Set the velocity of (Last created floating text) to 120.00 towards 90.00 degrees
        • Floating Text - Change the fading age of (Last created floating text) to 1.50 seconds
        • Floating Text - Change the lifespan of (Last created floating text) to 1.60 seconds
      • Else - Actions
    • If (All Conditions are True) then do (Then Actions) else do (Else Actions)
      • If - Conditions
        • (Level of Aura of Greed Merchant Job 2 for (Killing unit)) Equal to 2
        • (Unit-type of (Killing unit)) Equal to |c00FFD700[Merchant] - |c009400D3[Job 2]|r
      • Then - Actions
        • Player - Add 15 to (Owner of (Killing unit)) Current gold
        • Floating Text - Create floating text that reads +15 gold above (Killing unit) with Z offset 0.00, using font size 10.00, color (100.00%, 100.00%, 0.00%), and 0.00% transparency
        • Floating Text - Change (Last created floating text): Disable permanence
        • Floating Text - Set the velocity of (Last created floating text) to 120.00 towards 90.00 degrees
        • Floating Text - Change the fading age of (Last created floating text) to 1.50 seconds
        • Floating Text - Change the lifespan of (Last created floating text) to 1.60 seconds
      • Else - Actions
    • If (All Conditions are True) then do (Then Actions) else do (Else Actions)
      • If - Conditions
        • (Level of Aura of Greed Merchant Job 2 for (Killing unit)) Equal to 3
        • (Unit-type of (Killing unit)) Equal to |c00FFD700[Merchant] - |c00DB7093[Job 3]|r
      • Then - Actions
        • Player - Add 15 to (Owner of (Killing unit)) Current gold
        • Floating Text - Create floating text that reads +15 gold above (Killing unit) with Z offset 0.00, using font size 10.00, color (100.00%, 100.00%, 0.00%), and 0.00% transparency
        • Floating Text - Change (Last created floating text): Disable permanence
        • Floating Text - Set the velocity of (Last created floating text) to 120.00 towards 90.00 degrees
        • Floating Text - Change the fading age of (Last created floating text) to 1.50 seconds
        • Floating Text - Change the lifespan of (Last created floating text) to 1.60 seconds
      • Else - Actions