Thank you for all the useful info! Never stop writing down the obvious stuff, and some stuff in GS isn’t as obvious to everyone as it might/should be [eg: I never knew the tiny scissors icon in the Item Specifics section will, when clicked on, trim the length of the value to adhere to the maximum allowed by eBay].
Sadly, I do already know about the copy/paste attributes as I have used that quite a lot. But also sadly, not many of the cameras I got are the same model [or the ones that are, are a different color w/ a different UPC hah!]. But there’s a few that are the same model, so I think I will save them for last [always like to do the most time consuming stuff first 
].
I am curious how the eBay API allows huge data retrievals from its database, yet you can’t stick the same data back into it - eg: pulling 75 attributes, but only able to send 45 back. How did the 75 get there to begin with?
What I’ve been doing so far is just deleting attributes based on [IMO] usefulness. Like one I accidentally kept in for a listing, but deleted on others, was “Special Effects: Vivid Audio Red” which is….what? for a point and shoot camera? Huh? Hahah… [and I’ve been a professional photographer and sometimes still am!].
I have a boat load of other electronics to list too; this is going to be….time consuming…aaaah. [I’ve been doing books & media for soooo long that lately I’ve been acquiring inventory of other kinds of stuff to help keep my interest in this biz. But now I am discovering some of the quirks of GS as I explore these other categories.