TT will be over on friday 6th
Not that it is terribly busy during that week - I called yesterday for a slot on the final day, no problem.
Manx Flyers are nice people - £10 handling, free parking, landing fees are standard wherever you park (about £11 per tonne I think). If you want the red carpet Island Aviation charge £40 handling, £3.75 a day parking, plus the landing fee.
Don't sweat the water - plenty of people do it every day. Go as high as you can manage for the "warm fuzzies". The engine doesn't know it's over water!