What's the rate of evaporation/loss of a full synthetic engine oil?

Wow! 0W-40? Haven’t seen that on the shelves yet.

Oil consumption is dependent on several factors. Viscosity, engine break-in, average RPM, tempertures, and to some degree, metallurgy. Ignoring the latter 2 for now, the thinner the oil at operating temperature (the 2nd number in the viscosity rating) the more likely the oil is to pass the rings. Higher average RPM means more piston trips up/down and hence more combustion cycles and more oil consumption. Higher revving small engines will use more oil than larger engines, all else being equal. Then there is the piston travel, bore diameter and the mathematical considerations of exposed/swept cylinder wall area.

Engine break-in is, in my experience, the most critical. Most manuals tell you to drive with varying speeds for the first 500 miles or so. This varies piston ring loads and helps rings to seat properly under constantly changine load/no-load conditions. The very worst thing you can do is to take a brand new vehicle out on the highway, set the cruise at one steady speed and drive for hundreds of miles at the same engine RPM. That’s why I would never buy a “new” vehicle that had been ferried across the state from another dealer. I get blown off the road frequently when a new vehicle flies by with a temporary dealer tag on the back.

I properly broken-in engine shouldn’t lose more than a quart of oil between changes. I’ve driven cars for many years now, most of them purchased new and all of them traded at over 150,000 miles and never needed to add a quart of oil at 3-4,000 mile change intervals. My current 6.0L LS2 uses about 3/4 quart in 4,000 miles with Mobil 1 5W-30.