WestJet leases two Thomas Cook 757-200 aircraft to operate the YYC/YEG-OGG/HNL flights over the winter.
I'm not sure if they offer the "premium economy" or not.
Here is the seat map from seatguru for the aircraft:
http://www.seatguru.com/airlines/Tho..._757-200_B.php
The only thing that has kept me from booking with WestJet on these non-stop flights is if an issue comes up (aircraft goes mechanical) you could get stuck and lose time from your vacation waiting for a plane. I'm still sticking with Air Canada and their seasonal non-stops for this reason. Plane goes mechanical? Fly me to YVR, SFO, LAX or others to connect to flights to Maui (or they can get some spare metal faster than WS to replace the bird).