Allrightey then, lets not get our shorts bound up over this problem. From what I have read, your problem is:
1. You dont know what your true load is.
2. You want to be able to maintain 65 degrees.
3. You dont care about the RH% in the room.
4. When you crank the stat to 65 the thing freezes up.
5. You're not sure how to fund the convention.
My questions would be (and I know if I read the whole thread I could find the answer, but you know).
Does it freeze up with the stat at 65 and the ambient temp up?
It has obviously been running fine for a couple of weeks at 70, has your ambient temps been cold.
I was going to ask why cant you find anyone in S. Florida worth a sh*t, but I guess that is actually part of your problem.
Bottom line is the thing freezes up on you, isnt that the real problem you have?