1475 @ .5ESP might deliver 1200 cfms at .65 ,1200 cfm @ .5ESP is just that,so if the ESP is more than .5 ,the new air hanlder might not deliver the proper cfms.

Hot water air handlers that I've look into,are designed for the north.Meaning 60,000 btus of heat has enough air flow for 2 tons of cooling,where in Florida ,it might need a 3 ton system.

Large developement east of of was convinced by the the gas company to go that way,heard the ripped about about a hundred of them when summer time rolled aroud.large builder of ours ,got the same pitch,we said the gas company or the builder needed to sign as being responsible for the air flow,end of story.

Hoping the OP's air handler has the sir flow needed,maybe it does ,just be aware.