I am happy that You like it. I am shooting with Tele-Tessar 4/350mm FE with permanently mounted Leica Griffschale (for R-lenses). It is very comfortable to use then, but I lacked a grip. If shooting vertically (especially with such large lens) it have to be very useful, as You refereed to me.

Very nicely captured! Which tripod you're using for this heavy telephoto lens?