No one said boo to me last year about being alone in my 7×9 foot three man tent. It was not atypical for one or two riders to use a tent that size.
My “favorite” online tent review was for the tent I bought or a very similar three man tent I was considering at the time. The reviewer blasted the tent because it was too small for one person! How could this be, I wondered? Later in the review he mentioned that in his opinion a one man tent should be able to hold his inflatable queen sized air mattress with room to spare! The occupancy ratings of tents is based on users who like to sleep sardine style with their traveling companions and so they have to be used with care but this reviewer was being completely unreasonable.
But not completely atypical. I saw quite a few people dragging large air mattresses over to the phone charging station my charter provided last year so that they could blow them up using their internal 110V inflators. You need to us a fairly large tent for you occupancy rate if you want to do this but neither I nor anyone else seemed to think less of them for taking up extra space.
Having said that, jwsknk raises a good point. Well before RAGBRAI do a practice packing of all the gear you intend to bring along. The size and weight of that may, or may not, suggest to you that you downsize your tent and other take alongs! The Register limit is fairly tight and absolute. Whatever alternate team or club charter you may use will have their own limits, usually more generous, but in the end you will have to haul your gear so consider your own limit too!