I would run Delalum bushings for the eyes.  Stiff for performance, quiet for sanity.

Eye placement depends more on where you want the rear end to sit.  If your tires are close to max width I would not change the eye location because you may end up with rubbing that wasn't there before.  If not then I'd want it to pair well with where the front end sits.  A little higher in the rear looks fine, but higher in the front looks bad. 

What about specific manufactures / Brands ...
                          Who you purchased from   ..  what's was the cost ?? 
 ??  "     Nos681  "   "  5 leaf mid-eye...  --   Sits approximately 26” (ground to fender lip) on my coupe."
​
what about from top of fender to center of axle hub  - measurement "  ?
 

Approximately 13-7/8” (+/- 1/8”)
Still using rubber bushings...lubricated of course.

Mustangs Plus before the Magna brand in early 90’s.

If you go with 4-1/2 might be less harsh, perhaps lower stance as well.
This more of a track, smooth interstate only kinda spring.

I still have KYB Gas a Just on rears...changing to Vi-King in near future.

Also removed and sold rear sway bar last year...too much oversteer...thanks BB2 for advice.


ABSOLUTELY have to take it easy on washboard roads with 5 leafs and KYB’s.
Might have to JB Weld fillings back in your teeth and a tow truck to get ya out of the ditch.
Neither happened to me, I felt that way a few times though.
Of course common sense told me to slow way down.😂