Once you get the seat style and reach figured out ... you'll want to determine the correct heat range.
The NGK rep was out educating us counter people on what "heat range" really means.
He likened it to a thermostat in that a plug has the ability to draw heat AWAY from the combustion chamber.
Don't be afraid to make a call to the NGK tech line (1-877-473-6767, ext #2) with your setup. Those guys have valuable insight, and are there to help.
(I love NGK plugs, BTW)