From an old man's perspective (yep! I'm old), neither boat is big enough to live aboard. I had a 1978 Catalina 27 powered with a 30-HP Atomic-4. The boat sailed like a dream, it was really fast, both under sail and using the iron jenny, and going out for 10 to 15 days at a time, mainly on the waters of Chesapeake Bay, was lots of fun. BUT! By the end of 15 days that boat really seemed a lot smaller, especially inside. I had a sailing buddy with me, he snored like a grizzly bear with a head-cold, and on a hot, steamy, rainy night sleeping in the vee-berth was like sleeping in a sauna. There were lots of nights when the best sleep was obtained while under the stars with just enough breeze to keep the bugs at bay.
The vee-berth was about 7-feet from end to end, the quarter berth was about 6-6, the head was really tight, but I had a bit more headroom than the newer boats, with about 6-3 everywhere . Some of the newer boats had a different deck configuration which provided more flat walking surface, but the headroom was less than 6-feet in most places.
With this in mind, I looked long and hard at older boats for the best live-aboard specifications--not the best sailing specs. It came down to 2 choices, the Morgan 33 Out Island and the Morgan 41 Out Island. Next, this was narrowed down to which boat I can easily sail singlehanded. The 41 was just too much boat, at least for a 71-year-old guy with some missing body parts. On the other hand, the 33 turned out to be a piece of cake, plus has as much space as most conventional 41s.
It took 2 years of searching to find one that I liked and could afford. I drove more than 5,000 miles on several trips up and down the east coast of the U.S. before finding one just 50 miles away from home. I've been working on the boat and sailing it for the past two years, the work is nearly completed, (would have been done a year ago if I would have spent less time sailing and more time working), and this October I'm sailing south to the Florida Keys, Dry Tortugas and Bahamas for the winter. I'll be living aboard the entire 7 months I'll be gone, which is something I don't think I could have done on the Catalina 27.
If I were younger, and in your shoes, I would seriously consider looking into a larger boat. There are loads of good, used boats out there that would make a much better live aboard than either of those you have listed. Someone posted above that living on either would be about the same as living in a conversion van on the beach. While that may be a bit exaggerated, it's not far from the mark.
Good luck on your search,