Quick opinion - giving Euros the East Coast preference is probably not entirely desirable for a North American cup. It's fine when it's a Europe vs East Coast or Europe vs Central, but Europe vs West Coast players can skew the favors against the West Coast players (who should have the home advantage in a North American tournament). If you take three equally skilled players from Europe, East Coast, and West Coast in the current configuration, the East Coast player would have the advantage over the Euro (which is fine - North American tournament), but the Euro might have the advantage over the West Coast player depending on the West Coast player's connection and routing. And a lot of West Coast players have notoriously horrible/inconsistent routing to the East Coast.
In the BOXR tournament, we had it set up like this:
Euro vs East Coast: Played on East Coast server
Euro vs Central: Played on East Coast server
Euro vs West: Played on Central server
Of course if the players wanted to play on whatever server, that was fine too.
Anyway, I'm not playing in the tournament (will be working), and I hope it all goes smoothly. GLHF!