Thanks all. I appreciate the consideration. The verdict's in: dry suit and hot tea w/lemon, honey, and cream.
I don't know that I'll be able to pull off purchasing a Kokatat onesy dry suit. I certainly will don a thick, full-length farmer John, with thick under top, plus a good paddling jacket.
dsrtrat: Yes indeed, I well remember those days too: wool, and bunting. And indeed that was a nasty swim and it effectively puts the matter into perspective. We will have several excellent safety boats ---hopefully no one on the trip will face a swim like that.