Troels,
Well, I have been playing with my 1000Ms, and managed to make them sound fantastic. I have gone off the idea of making new sexy boxes for them, just repainted the originals.
I will however make black subs to go under them, as discussed. In fact they are sounding so good now, that this may not be needed....
I tried a higher resistor on the tweeters, but reverted back to the nominal you recommended. Sounds best.

I also played with the amount of damping material inside the box. I can say that with their standard stuffing, the bass is overdamped.
I removed half the material behind the tweeter/mid, and quarter of the material behind the woofer. Much better bass, and energy now, and they go deeper also. I am getting more mid bass as well, which balances the top/mid a lot better.

Also had a comparison session with my mates standard NS1000Ms, and can say that mine ones are head, and shoulders above in every way. Better bass, better mid bass, smoother midrange (without hardness), and better tweeter integration. SIMPLY SUPERB!!!!!
It may also help, that now I have about 50 Hrs of listening on them with your crossovers. EVERY NS1000M SHOULD SOUND LIKE THIS!!!!.
I will make the subs, which should improve an already fantastic speaker, and will send photos including your crossovers inside, the blanking plate, and the subs.
May take me a month or so.
Cheers: Tim

Troels,
All complete now, check out the photos. Made the sub boxes out of 25mm MDF. Sound fantastic with the much improved Yamahas. Adds that extra bottom end.
I made the subs the same footprint as NS1000Ms with grills on (not that I use grills with them). Internal net volume of subs 37 litres. Sub drivers are Peerless XLS 10”.
Made the sub grilles the same shape and size as the YAM 12”. Look pretty sexy. I am a very happy man. These are the ULTIMATE NS1000M. Thank you for all your help.  
My next DIY project is on its way...building a pair of Proac Response 2.5 with your V6 crossovers. Will keep you posted.
 
Cheers; Tim