You can get two man tents that are light and compact. That being said, I bought a Passage One tent by REI for use when I don't want to use the Warbonnet Blackbird hammock. It was on sale. The price was just too good to pass up. I can strap the poles to the top tube of the bike, and the rest can be put in its stuff sack and a dry bag, remaining fairly compact.
I just used it on a motorcycle trip. I was able to put my 40L Ortlieb duffle inside, along with my large tank bag. It has a bit more room inside than many single person tents. My bicycle touring gear fits inside even better. My Ortlieb Back Roller bags fit inside nicely, along with my handlebar bag, though I generally leave my bags attached to the bike and bring in only the handlebar bag. A saddlebag also fits in the vestibule.
Two man tents simply give you a bit more room, and that is nice. When looking, be sure to compare the floor space, not just the description, one person tent vs two person tent. One reason I opted for the Passage 1, is that the floor space does not taper at one end, so if gives you more room than those that taper. I generally use my hammock on tour, but on my last tour my wife came to spend the weekend with me. I had her bring out three person Coleman tent. It's huge. It gave us plenty of room though, and I kept it for the remainder of the tour since I was potentially going to wait out some bad weather, hail, heavy thunderstorms, high winds, and temperatures in the mid to upper 40s. It weighs 11 pounds, but it was nice to have the extra room to lounge in.
Generally speaking, go bigger if you have any doubts. You are not hiking, carrying the tent on your back. Better to have the tent a little bigger and have the extra room, than have it be too small for your liking. Whatever you get, try it out before taking it on a tour.