I live in a 1700 square foot house in Houston (humid). Got a new AC 10 years ago. The installer recommended 4 tons (Trane XL17 2 stage), but I'm wondering if they sold us something too big to keep humidity down. Is there anything we can do?

For more info, we don't have any high ceilings. The house was built in 1975 and still has the original thin windows, some of which are quite large.

Really I've got two questions. I've been researching dehumidifiers (portable and whole house) to try to solve the high humidity in the house during the times of the year that it's too warm to run the heater but not warm enough to run the AC. So question one would be: what do you recommend for lowering the humidity during those times?

Researching dehumidifiers is what led to the articles about how a properly sized AC should do the work of a dehumidifier, which led me to the second question that I asked in the title. Thanks.