Hello Terry, how nice to hear from you. My HDS is sort-of-completed but is currently disassembled and in storage. You see, I was a little unlucky and had to spend most of the last 6 years abroad in hospital. Very frustrating. I'm okay now, though, and gradually attempting to resume normal life.

The jobs I left myself were installation of the engine and prop (I have a Rotax 914 in storage), and the instrument panel. I had put off buying a prop largely because the turbocharged engine necessitates a constant speed one and they're really expensive! The one that I thought looked best was the Airmaster... 
https://www.propellor.com/ap332-wwl70z

There are a couple of other little improvements on the HDS design that I'm going to make. Firstly, vortex generators which should knock a few kts off the stall and slightly increase cruise speed as they mean you can keep the nose pitched down a few degrees. Secondly, wing root fairings... 
https://personal.utdallas.edu/~klaus/Airplane/wing_root_fairing.html

I'm really impressed you've got 600 h on yours. I can't wait to get mine in the air. Fortunately my brother is an airline captain & instructor so can help remind me how to fly!

Regards,

Jonathan