So I just bought a Hegel H390 and

As some have noted... the Hegel amps are especially great at driving Harbeth speakers.

I have the H590 - which I bought especially because it sounds so good with my Harbeth 30.1's and 40.2's - just as Alan Shaw has suggested.  

It has the power / current / damping to control the woofers / mids to provide the clarity the Harbeths need.  

Just as it does here:

https://www.youtube.com/results?search_query=harbeth+30.1+with+hegel

A store near me that has Hegel usually demos them with B&W speakers so that should work great. 

Harbeth 30.1’s with a pair of RELs. Sounded great with my H590. Wilson Sabrina X’s sound even better but a bit more than your 10K budget.

Congrats on a very wise choice of amp. A friend has the 590 with Focal Kanta 2s in a room similar size of yours. I thought it would be a little bright for my tastes but it was not. 
The beauty of the Hegel is it can run sensitive or not so sensitive speakers so you have many choices. Several good ones above and
in another 12 months you might manage to hear them all.
You can go for max detail, max warmth or somewhere in between.
Open Baffle, Box or planar/electrostatic are all quite different.
Get some good XRCDs and start listening. 1st stop RMAF in Denver
in October. Love to know what you buy.

The Hegel drives 390 drives just about anything with aplomb: the world is your oyster. Try whatever tickles your fancy that suits your room(s) size and budget.

Because there is such a wide range of possibilities out there it is impossible for a third party to make the right choice for you.