Yeah, I see what you mean by waiting till end of movie to measure screen. It's unlikely I'll do that because I don't own a digital measure, and I might not want to take it with me & go to those lengths during the occasions that I do go because probably wouldn't be a solo adventure, & I don't know when I'll be going next as disappointed in the sound (visuals I found great) and a bit concerned for my ears too, plus if my track record continues re cinema attendance then it'll be 10yrs till my next viewing!
(If could find a way to talk to the techs then just asking is an option. Perhaps even customer support queries over internet or whatever.)