Thanks for the feedback! It makes more sense now. We considered casement windows but chose these because the casement windows would have opened at a very awkward height in our backyard.
We haven't had any condensation issues on these windows, possibly because we do use our range hood and bathroom fans as you suggest, PEIslander. One thing that surprised me was that there was still infiltration even after I covered the weep holes, but after posting I noticed that the website says, the inner sash perimeter is equipped with fin-type weatherstripping to prevent air and vapour leaks, which implies that the outer sash perimeter was intentionally designed and manufactured without weatherstripping.
I'll uncover the weep holes and ponder whether to install some window insulation film. It's at least as good as our previous windows plus the film; it's just not as cozy as we'd like. There's also an exterior door in the same room, so I'll look into sealing that better rather than focusing on the windows.
Our place is lower-level condo in a quad-plex that's 90 years old, and we pretty much always have incoming drafts from both ends of our place. I suspect we're losing heat upwards. There aren't any obvious paths for the air to take, but I haven't searched intensively because it seems like a big, open-ended problem with small returns and we're not certain we'll stay here for life. When it's cold enough outside, we even get cold air coming down the chimney through our wood stove/insert at the opposite end of the place. One day I may swap that stove out for a natural gas insert that takes its combustion air from outside, but that's a whole other kettle of fish.
Thanks again for your insights!