If it was me, and the range was 500 yards and beyond and I wanted to stick with a Nosler in a 7mm RM then I'd go with the 160 grain Accubond. Hell, I'd use it over your other two choices for everything unless you might want to use the little pill for varmints.. This is a range where you will have to compensate for bullet drop and drift, and will, hopefully, dial for the longer ranges.
With a good laser rangefinder, distance estimation is not a problem, but wind will be a killer, and the 160 will have an even higher BC than the 140, with the resulting benefits to you.;) Go here and you can play with the numbers.
Ballistics Programs (Web based & Downloadable)
Under 500 the choice is up to you but beyond that, "BC is your friend".