With the instability problem out of the way I've used the Nouveau on the air and can report that it received rave reviews on this morning's Midwest Classic (AM) Radio Net on 3885 kHz. From my QTH in northwest Illinois the reports were "loud and clear" and S7 to S9 from Detroit and St. Louis (250-300 miles) and "10 over 9" from 60 to 80 miles away. Several commented favorably on the audio quality.
Now the rest of the story: When I first checked in I was using a small converted CB amplifier using a single sweep tube that produces a resting carrier of 20 watts and 80 watts PEP on voice peaks. But I switched the amplifier off before asking for signal reports and all the above were on the barefoot signal, not through the amplifier!
Clearly the amplifier makes a difference but this test just proves that with a clear frequency and good antenna (full size 75 meter dipole at 50' in this case) the barefoot Nouveau 75 can do a fine job.
Here's a picture of the Nouveau 75 on it's D&A "Hawk" CB amplifier perch: https://i.imgur.com/cuFVzBl.png
I'd converted the amplifier to 80/40 meters some time ago, replacing their inefficient tank circuit (except on 11 meters, for some reason?) with a tapped toroid and upgrading the power supply. It uses a single 6KG6 and would be an easy project to duplicate using most any sweep tube - the schematic can be found online.
73, Bob W9RAN