If the beam of your boat exceeds 8'6" you are required to have an "Oversize Permit." Don't know about the other information you posted (ie. width between trailer tires) as that may be a requirement of a state other than Florida.
One of the above Posters who said your chances of getting a ticket for towing an oversize boat are very slim, but if you get a ticket that would be the least of your worries. Why? Chances are if you ever do get a ticket for towing an oversize boat it would be because you were involved in an accident, and if this were to occur you better have deep pockets and hope that no one was injured, because if there was an injury, regardless of who was at fault/who was cited, if you are towing illegally and your insurance is void.
Think about it. You come up to the stop sign and the car in front of you stops to fast for you too, and whacko you rear end him/her and there are injuries in the car in front of you resuting in a multi-million dollar lawsuit with you cited for read-ending AND towing an oversize load without a permit. But more importantly, since you opted not to bother getting that $20 permit (or renewing it if you had one) you now have no insurance coverage because you knowingly violated a state law. Kiss your a**ets good by.