I'm in a similar climate and have an oversized unit on the roof of a condominium building . Perfect for us would have been a 1.5 ton unit but the installer put

I'm in a similar climate and have an oversized unit on the roof of a condominium building . Perfect for us would have been a 1.5 ton unit but the installer put in a 2.5 ton and told us it would be fine. Reality is... The temperature rises and the AC kicks on. The plenum chamber in the AC unit, which is near the roof and is hot is flushed out to the condo interior. So we get a blast of hot dry air, followed by a blast of cold dry air for a brief period. The large unit quickly cools the condo and then switches off. So on a hot day the unit is cycling all day. This still happens on the hottest days of summer [in contrast, perfect would be a unit that, in the hottest weather, turns on and runs all day, barely keeping up]. To boot, this raises the electrical bill and stresses the AC unit. So don't get a unit that is too big. Go to the trouble to have the unit sized properly. The dehumidifier sounds great but it will decrease reliability and be one more thing to fail. It might be worth trying. Definitely don't use it with an oversized system - use it with an undersized system!