Yup, definitely dry suit is the way to go. It's amazing what couple of degrees cooler will do. Going from 10 C (50 F) around Vancouver to 8 C (46 F) makes a big difference. What kept me plenty warm around southern BC was downright chilly in Port Hardy. Luckily, I had brought my old fusion dry suit as a back-up, but more importantly, the big thick MK-3 undergarment that goes with it. I thought I wouldn't need it anymore when I switched from the fusion to my crushed neoprene, but after one chilly dive with the MK-2, I pulled out the MK-3 and was ok. Mind you, I had to add back on the 8 lbs I thought I didn't need anymore, but at least I was warm! (I froze my butt off last year in PH with the fusion + MK-3 + every available piece of underclothing I brought, so I am still a big fan of the crushed neoprene).
With the MK-3 crammed under my crushed neoprene, I would stay warm for the typical 45-50 min dives. It's only when I did some longer dives (I think we did 79 min as the longest), would I start getting chilly towards the end.