The first time I went across was in an 18 Outrage; it was choppy and 10-15kt and we were fine and had no concerns.
I get the "if you have to ask you probably aren't ready" thing because it's really the pilot, not the boat. But before the first time I went, I had to ask, and the whole first year I was doing it regularly, I researched it constantly to see if I was missing information somewhere or something. In that sense, you can be doing it, and still asking a lot of questions.
Anyway my experience is that if you try to stay under projected winds of 15 knots you could do it in most 17+ boats without too much trouble. The worst conditions I have seen on any crossing were always around Sand Heads anyway. Somewhere I have footage shot from the back of my boat of a 31' Silverton, I think, a big flybridge cruiser, hull surging completely out of the water, barking props as he tipped over the crest, and disappearing between the swells behind us after we'd gotten through the rough water at Sand Heads. He'd vanish from view completely between waves.
But after that it was pretty straightforward on that same trip...once we were away from the rivermouth it was rough and we had to idle the whole way across but the only nerve-wracking part had been the mouth. After that we were just getting rolled around but no waves sweeping the deck or anything. Even when the big flybridge was disappearing from view we were laughing and joking about it, because the previous trip had been so much worse. Again, right at Sand Heads.
So I would say that if you're comfortable getting a couple of miles out from Vancouver, well, you don't really hit anything much worse out there in the middle. Bigger, sometimes...you do see 6' rollers and occasionally more...but they're not really dangerous unless they're breaking, and they aren't breaking unless it's really obviously a bad idea to be out there.
The main issue is really just that if you're in rough water and two miles from home, it's nothing. Twenty miles away through water you can't get on plane in means that much more time for the weather to get worse, so you do have to keep an eye on it.
Anyway, bottom line...I'd take an open 17' Whaler or a closed-bow 17' whatever in projected winds that were under 15kt and if it was predicted 5-10, I wouldn't think twice about it.