Which Amp to complete my system?

Check out the Quicksilver Mid- Mono amps!

http://quicksilveraudio.com/products/midi-mono/

For solid state look into the Digital Amplifier Company I have had STM on my horns and if I didn't found the deal on my mono 300b's I would still have it. Very clean, clear, and smooth with 0 digital etch. Contact Tommy he will set you up.
https://www.cherryamp.com/
For tubes look into Audio Note Kits 300b amps. Very well made and very good performers. I have had the Kit 1 and now have the Interstage Mono's SET 8w.
http://ankaudiokits.com/ANK-Audio-Kits-Home-Page.html

With Don Sachs you get a lot more for your money, much like Schiit Audio he sells direct to market, and using Maida filters his DC is dead quiet, a must for high efficiency speakers, as well as for maximizing detail and timbre. You should at least give him a call before dismissing him. 

http://www.dsachsconsulting.com/custom line stage.html

I love my Rogue Stereo 100, modern powerful tube amp. See recent stereophile review.

A good Audio Research Reference 75SE. I have a few that I am selling in the store. Tubes will lend themselves to a bit warmer sound. If that's your cup of tea.