Set TGR sp-param automatically based on formation slot?

Hey all. I'm trying to duplicate the formation system to that on FF1 on NES.
Basically, the party member in Formation slot 1 should be targeted more by enemies than those below him in the formation, and the same goes for the guy in slot 2, anyone below them is targeted less.. etc.

I figure the best way to do this is to have the party member in Slot 1 have 100% "tgr", and have slot 2 have 90, 3 have 80, and 4 have 70. (I'm honestly not sure how enemies access this stat to decide targets, but I hope that 70 on one character wont make him NEVER attacked... because that would be bad. XD)

So, as for changing the members tgr based on where they are positioned.... is there any good way to have it done automatically without making a "state/conditional/comment event" for each slot that have to be added/removed/swapped all the time when formations are changed, (and hidden since its a background thing).

Any suggestions? I have all of Yanfly's plugins at my disposal if any of those would be useful for this...
Thanks!

the easiest option would be to make these states assigned with a troop event. run the troop event at end of turn and have the TGR states a duration of 1 turn, or run the troop event at the beginning of each turn and give the TGR states a duration of 2. then have that single troop event assigned as a base troop event (to automatically run it in every troop)
anything else would require more complex parts or plugins.

Hm... Perhaps this will work... although i would only have to run it once at the start of battle as no formation changes can be made during battle in my game. I'll just make the states "remove at end of battle." And use Yanfly's State core to make the states hidden.

I'll give it a go and let you know.