Thanks so much for your responses, Ian and Loris.
I tried a couple of prints this morning... one without sizing and one sized with Gamblin PVA diluted 1:3. Both turned out decent, though the one with no sizing took much longer for the highlights to clear. The Gamblin seems promising at this point. After it dried, it didn't have the odd sheen that I remember it having the last time. I haven't put a second layer on yet though. One problem that I did have was how badly it made my paper buckle. This made it hard to spread my emulsion evenly.
My bottle of glyoxal should arrive sometime this week. I'm looking forward to experimenting and seeing which method I end up preferring.