One heck of a post Brian! And especially about the harmonics, without them there would simply be an electronics futility.
Tiggar, strangely enough I discovered the opposite with mine, I thought my Sov did well on the beach until I got my cz-70. I traded the Sov for a $1000 Browning A-Bolt 338 mag (with scope) and thanked God for the sweet swap. It bagged a fat deer this year.
I still have the CZ, it's the deepest detector I have ever owned or seen on Oregon high salt/high black-sand beaches for coin hunting (running in zero notches), period, no exceptions.
One outfit down in the deep south somewhere quit pushing Nauties after the F-75 whupped the Nauties so severely in the GNRS. Now he pushes Fishers. That's what I was referring to about he GNRS. Of course most detectorists know that already, but I thought I'd mention it. Basically it all comes to "the proof is in the pudding".
You all have a fun-wun.
LL