Fantastic Ken, good to hear, i understand totally where your coming from, its just some people don't have the strength to hand hold, I do you do.
The OP indicated "Weight is also an issue as not young anymore, and the 180-600 is too heavy for hand holding"
200-500 is 2.2 kg, 200-500 is 2.3kg 800pf is 2.4 kg so it may be in there case at least a mono pod is essential or needed more so than for others to achieve the very best outcomes.
especially should the light be lower or the ISO is getting to high.
I mean we know a mono pod or tripod adds that bit extra sharpness and lets us use a little slower shutter speed and keeps the ISO at bay, LOL
i mean i even use a light mono pod with my DF D850 and 50 mm or 24-70 doing street come city photography, only because i want the very best outcome, its defiantly more noticeable especially if the light falls slightly.
The 600 F4 Tc is so exceptional in low light, just amazing, the one thing to watch out for regardless of brand is generally in lenses with built in Tcs is that over time or heavy use its important to check the Tc alignment is keept in check, somthing experinced from time to time with the Canon built in Tcs, they sometimes need to be tweaked back on point after say 12 moths of hard use. That doesnt happen with everyone, its very much use dpendandt.
When i hike around Cradel Mountain with a 50mm or 24-70 on my DF or D3X or D850 i use a light carbon fibre mono pod, or more often super light small tripod.
But that doesnt mean other peopl do, my girlfrend laughs at me, she uses her phone and does macro and landscapes with stunning results.
Happy days