The 8000 series might have a new product number for the tweeter - I only have experience with DSP6000's and below.

The H1212 is here Seas H1212.

I found the specs for the H539 somewhere but can no longer find them...

The non milennium Excel is the one I recommend - but you need to take the flange down (any one with a lathe can do it) and make a notch for the 180 degree terminals to fit it...

Not sure if I had a set of 8000's if I would mess with them though, older speakers yep.

Roon/Tidal, SBT, Trinnov ST2 , Twin Devialet D premiers, Vivid Audio Giya G1 Spirits, dedicated and treated room.
Meridian gear: 568.2mm and DSP5000's acting as TV speakers.