I have some experience here..
I used a low profile Carrier on both my Caravels and the Flying Cloud, and the 21 ft. 94 Sovereign
. As Andy said...the profile means nothing to the fit. (There is a small interior unit fit problem with the 94.) In Texas I have found that the 15000 is the only way to go and be comfortable. The 13000 just does not have the "umpfff" needed. If you don't get in a hurry you can still find a Carrier LP in stock at some locations...and they show up at places like Colaws.
"If it can't be reduced, reused, repaired, rebuilt, refurbished, refinished, resold, recycled or composted
then it should be restricted, redesigned or removed from production."