Result of all this...
I am now a happy customer once again
After an email marathon with 4 Wheel parts and Tenneco (Rancho), I finally had to get something done, so I went out and bought 4 new Bilsteins ( thanks to all your suggestions ) and had them installed. We found out that the passenger front shock was not only loose in it's mount, but was totally shot, no dampening at all. The rear on the same side was considerably weaker than the right side, although not as bad as the front.
The Bilsteins give me an awesome, smooth ride, just -slightly- stiffer than the OEM's but totally enjoyable. I should have done this originally. The Bilsteins, BTW, are a gas-charged shock, the Rancho's are not.
Finally, the East Coast rep contacted me and is refunding my total cost for the Rancho's.
He was very polite, concerned about my runaround with Tenneco, and was able to solve my problem to my satisfaction quickly.
Thought you might want to know how things turned out.
Thanks to all for your help, suggestions and advice based on personal experience.
Robert