Thanks to everyone who contributed responses to my original question. I have decided to install a Magnum PSW to solve my problem. And, as expected, I learned a whole lot more about inverters, test tools, and most importantly the skill set and willingness to help of all who responded. I really appreciate it.
Separate subject. I just finished a two day school at Freightliner in Gaffney, SC (Camp Freightliner) and found it very informative. It was for RV people only. They also have a dedicated RV service center there which I also took advantage of. Good folks, professional, very helpful and tolerant of those of us who know less than we should but are willing to learn.
Cheers to all.