I understand exactly what you mean, although i have a 2" flipper up top.

Are you using a 2" or 3" ?

Not that it matters, well it does a little, but to drop the power of the flipper you don't need to put in a different coil.

You can put a low ohm 5W ceramic resistor in the EOS circuit.
This way for a low cost you can try different values using alligator clip leads until you are happy. Try maybe 1.5ohm to start.

So attach a resistor of your choice to the middle lug of the flipper coil which joins to the EOS.
The 'flip' winding now has a voltage drop across it reducing the voltage at the coil.

You can remove one wire entirely, or desolder one end of the wire going from the middle lug to the EOS and solder in the resistor.

Hope this makes sense.

I contacted IPDB trying to find out what the game initially came out with?

Only recently did i notice that the rubber kit states 3 x 3 inch flipper rubbers, to me this suggests it came out with a 3" up top.

But having a 3" has it's pros and cons.

The tip of the longer flipper can get in the way of a ramp shot, but makes for easier hitting of X,Y & Z drops.

You could go 10 watt, but with it just hanging, not putting any strain on the flipper coil lug nor EOS lug, there is plenty space/air around it.
I find i don't get much time up top anyway ;(

You sound like you know your stuff and i'm sure you'll sort it out.

I had to add a resistor to the 'LOCK' kickout holes as when it kicked the ball out, the ball hit the glass.
I checked all the mechanical side of it and it appeared fine.......got me thinking now to remove the resistor and loosen the spring ? ......one day.

There is a comment on the IPDB Vector entry that Greg Kmiec included a small flipper on the original playfield design. The 3 Vectors I've had at home have all had large flipper at this position but Imo certainly small works better if only aesthetically.

You'll get less power with a 2-inch flipper. You can try using the higher resistance coil too. Targets breaking off from too much flipper power has always been an issue with this game.