Assuming you're driving to FW, I'd say plan to leave WBC no later than 6pm for the 7:15pm show. It'll take about 10-15 min's to drive to the FW parking lot. Then from there, you take a bus back to the "Settlement" within FW. That bus ride takes about another 10 min's, but sometimes you have to wait a bit for a Settlement bus to come by, so it could take some extra time to actually get back to where HDDR is. You'll want to be back by Pioneer Hall at least 30 min's before showtime so you can get checked in, get your picture taken, etc. You might have a little time to kill, but I like to be too early rather than too late.