I always do 20 minutes before a scheduled show and it's worked out just fine.
Don't know if you and your husband are beer drinkers but I thought I'd put this out here again for anyone else who is. My husband did a cost comparison (he does that with everything) and the large beer at the Biergarten is a good value compared to just a pick up beer along World Showcase at a kiosk. However, the large beer, is, well, large. I can barely lift the full one and finishing one at a meal is out of the question for me. BUT - a little known fact is that you can just ask for a "to go" cup when you are ready to leave and one will be provided for you. We go for lunch and that beer lasts me to close to Illuminations time and I get to enjoy the park as well.