Have you decided on a school yet? If you pick one of the schools that most people refer to on here (NAC, EFT to name two) you will find the school in question will help you with your visa process and explain exactly what it is you will need to obtain.
You have said that you want to get your fATPL, well you will need a Class One medical, your inital one has to be taken at Gatwick (if you want a CAA licence) this link will get you there,
http://www.caa.co.uk/default.aspx?ca...=90&pageid=527 It is best to get it now, rather than spend thousands on training only to find out you cannot get it.
Whats the best months???? No idea, most days in Florida are fine, watch out for hurricane season, so now's a good time. I went Oct to Dec 2003 most days were great, I am goiing back next month for my CPl/ME etc.
For which is the best aeroplane to fly...... well that s the most asked question, I have 160 Hours on Cessna 172's and 150's love them. I also have 10 hours on Piper Warriors and Cherokee's which I don't like as much. I would not worry about which is best at the moment you will love it all the same.
If you are hour building in the states, as I did, you might want to think about taking your FAA PPL/NR (it comes with night rating as standard). You only have one exam to take, but quite a rugged oral as well. Once you reach 100 Hours total (if i remember rightly) you can do the JAA conversion this happens to be 2 theory exams (Air Law and Human Factors) and a Flight Test. This option does not include your Radio Exam, I did mine over there as well but it does give you a Night Rating on you JAA licence.
Speak to the school you are going with and they will point you in the right direction.
Above all have fun.
FF