Cost of E-First Upgrades
 

How can I determine the cost of an E-First upgrade? NWA's site doesn't have any detailed info, just that you can do this when you use their kiosk to check-in for your flight.

I'm heading to AMS through MSP and back through DTW and we're flying a qualifying class (Q and H).

i don't know the cost, but imho, it's not worth paying to upgrade your TPA-MSP and DTW-TPA segments. you'll get a somewhat wider seat, maybe some more legroom (depends on your Y seat and aircraft type), and free alcohol (but you'll also be getting that on your international segments).

as for your AMS segments, those are not upgradeable using e-upgrades at the kiosk, but on rare occasions, GA's have been known to sell WBC upgrades at the gate for transatlantic flights, usually for $250-500 per seat.

E-First Rules Not Published
 

The E-First rules are controlled by the Marketing/Pricing department, subject to change, and therefore not published. However, based on the mileage of 1308 TPA-MSP you should be offered an E-First upgrade for $75, assuming the appropriate First Class inventory is available (I believe it was just changed to R from F).

There are currently no international E-First rules applicable to the MSP-AMS portion of your journey, and the program does not currently apply for the return flights out of Europe (since the kiosks are not NWA's).

Not quite true. There actually are upgrade possibilities on flights to Europe (not AMS) when using the kiosks; however, they are very few and far between and highly randomized. Therefore, it's possible for one person to be offered the upgrade and another not, even if they meet the same criteria and check in side-by-side. If you really want that WBC seat, it's best to either buy the fare for that cabin or use miles to upgrade.