I did Rope Drop at Epcot a couple weeks ago in an attempt to ride Frozen Ever After (I got sick and ended up not riding, but that's a different story).
So here's how it worked. At about 8:45, both the front and IG gates were opened. Right before the Mexico pavilion, ropes were strung across the pathway to block off the World Showcase. They also have ropes up at certain spots on each side in Future World prior to actually reaching the rides. At 9:00 (+/- a couple minutes), the ropes are removed and the groups gathered behind them can proceed to the rides - that part is where the term Rope Drop comes from, although it's usually used to refer to the whole process in my experience (since best practice is to be in place at the entrance well before start time to enter at 8:45ish and actually get to the ropes before they "drop" at 9).
The timing seemed about the same: the first arrivals from the main gate reached the rope at basically the same time as the first few from IG (and measuring the distance via map shows the distances as almost identical).
So if Norway is your destination, either gate should be the same - if IG is more conveniently located for you, then go for it! It's also a prettier walk, in my opinion, going past the UK and Canada pavilions instead of going through the center of Future World.
If you're trying to get to Soarin' or Test Track before a crowd forms, though, you're better off going through the main gate - because they're at the front of the park, it will take a lot longer to get there from IG than from the main entrance.