Santorini is about 100 nm from Bodrum, 170 from Marmaris and 130 from Athens. Unless you want to visit turkish costs as well, you better look for a charter
company located in nearby islands. Regardless the company is greek or Turkish, if you want to visit both of these countries you will need to make entry exit procedures. If you do yr self it can be complicated and time consuming, if you use an agency both side it will cost you app. 300-350 €.
Meltemi is always stronger in the Aegian channel (the middle of Aegiean sea) , where you exactly want to be..It may go up to 35-38 knots but normally is quiter after the sun set and early in the morning.
If you are going to travel all together 11 people + skipper
, you would need quite a big monohull
(54-55 ft) or a large cat (44-45 ft) which is not always easy to find. If you need more info PM to me, I can help you.