Get your measurements from someone in your area. We never had a problem with this. Just explain you need them for a cruise. Email your measurements. The tux will be in your stateroom either the day of arrival or the next day. We got ours the same day but was told it would not be delivered until the following day. We also got 2 shirts.
Also, if you have any problems simply call guest services. My DH had a shirt that he and I could fit in together. They were in our stateroom within 3 minutes with more shirts for him.