I appreciate all of the advice you and others gave. I still haven't learned to play, but I'll take it out every so often and strum and admire it. Whenever my friend that sent me that link comes over, he'll play it for an hour or so. I just have it stored in the case in my closet. I asked either the luthier that restored it or Gruhn about storing it and string tension and he said to just keep normal tension on it.
When I watched the video in that RetroFret link, I was underimpressed with the sound because it really can sound powerful. I have an employee that plays and has played mine. This is what he said after I sent him the link:
I don't remember them telling me much info on how many were made, but I found this:
https://www.vintageguitar.com/25116/gibson-j-35/
The J-35 was manufactured in far greater quantity than any other pre-war Gibson dreadnought, with an average of 380 produced each year from 1937 to ’40. The following year, J-35 production surged to 855, which topped production for all other Gibson models with the exception of the V-25 violin. Though the J-35 was an inexpensive guitar when new – costing about half as much as a Martin D-18 – today, it is held in high regard by collectors and musicians, its desirability and superb sound due not only to woods, but the fact it was lightly built with thin top and light bracing, which gives great power as well as fine tone. An unfortunate side-effect of that construction is that any examples not treated with great care frequently fall into poor condition. Luckily, those that are properly maintained are inspiring guitars, and prove that an instrument’s list price is not always proportional to the quality of its sound or its desirability as a vintage model.