Nice photo Barabarossa. I got a very old MARCO 4mtr conntional with a 35bhp Envirude similar to the Jonson that you have there. I got this boat to go fishing. It was 2nd habd and cost with engine and trailer Euro 500!! Good price I think.
Regarding meltemi is not that bad. If early in the moring about 7:30-8 o'clock you are ok. Also if late in the evening about 5:30-6pm is ok too.
The sea in the Aegean it doesn't get that big maximum wave hight is about 2 mtrs and that is if it blows gale forse 8+.
Usually is about 0.5-1.5 mtrs in Kavo Doro.
There are days in the summer not more than 5-10 in total (and not consecuitive) that it blows force 8-9. And although you cannot make a long trip is ok if you round th coves. Aegean is not a humid as the Ionian and I like this dry atmosphere better.
I was just telling Gabriele about you that you have joined this forum
He is thinking VERY SERIOUSLY to come to Santorini in the summer. Possibly take the boat and car to cape Sounion and leave the car and trailer in my house and travel on the boat to Santorini Just 90 miles and about 3.5-4 hrs on an average day.