Without getting involved with the myriad of details and understanding that if ever I was a golden-eared audiophile I'm sure not now, does the GR Neo-3 have a similar very-hi-quality treble that the B-G Neo-3 PDR has/had?
In 2011 I became dissatisfied with the quality of the treble of my Avantii IIIs' ring radiator (RR) and after a fair amount of advice (some advising me NOT to do it), I simply replaced the RR with a G-B Neo-3 PDR.
The treble sounded GREAT, and, to my surprise, it worked excellently with the original 3-pole x-over, so all I did was add a wool-felt pad.
I think it's time to do a similar thing with the silk-dome tweeters in my Vienna Acoustics Mahlers.
Of course, the FIRST thing I'll need to determine is how to remove the originals.