Preview's "Take screenshot" I use ( full screen to grab in program stuff like location datas, inspector etc.)
or the window and 'grab selected' for the custom spots. Doesn't change your doing a gorgeous work here Sevesp!
Also, in the rendering listings: "Save to file": you will get the final rendered as requested ( could be larger than your screen!) as you set up the 'wants'. If it's a known " I gotta have it" location, so what if it takes minutes to render? I don't care of time, I got the desired pic!