I find that it varies A LOT for Guardians. On average, I've waited 20-30 minutes though there have been occasions where the wait was 50-60 minutes and others where I almost walk right into the preshow. The VQ wait is definitely longer in the late afternoon/early evening time and I think it's because since Guardians isn't strict on your return time, people who grabbed VQ spots at 7 am are coming in at that time.
No idea about Tron as I only rode it via the AP preview but that line was an hour from scanning in to getting on the ride.