Well... that sounds like FUN! I think you will enjoy it. The 1/FL shutter speed rule-of-thumb is a good one, but we all know... with a steady hand you can go lower than that. So... the other nice thing with a 20mm lens is when you are out walking around... and the daylight starts to fade... if you are steady, you can hand-hold down to 1/4 or 1/2 sec (even without VR). But you need to be steady, of course. Although... with these wonderful digital cameras we have nowadays, you can also increase the ISO. LOL. On the D810, it feels nice and balanced. Compact. Easy for walk-around. Great for groups of people, in the city, interior shots, wide landscapes, even close-ups. Okay... now you are making me nervous! What if you are not pleased with it? LOL. It's a good lens. It's always fun to fiddle with a new piece of gear.
;-)