I sail a 45 foot by myself and have no problem for handling her. Most of 40 foot are roomy enough for two, a 45 foot give extra space. If your budget is high and really like to have space, then a 50 foot might be for you. Modern boats come with modern equipment. A good crew of 2 can easily sail a 50 foot modern sailboat. If you buy an older boat, you will probably welcome new equipment coming on board before leaving shore.
What boat to choose ? How to respond ?
What do you like ? Ketch, sloop, cutter, wooden boats, aluminium, fibreglass or even steel boat, it is almost impossible to answer.
I do have 150 gal of fuel
and I am fine with this. I am not in need of more.
I do have 200 gal of waters and I have installed a water-maker. I guess I am using too much water. I have a shower on deck, then when it is warm, it is easy to take a quick shower to get colder. But little showers after little showers, tank gets empty too fast.
About tax, here is some info.
You buy your boat in your country and pay taxes. When you return, you are all clear.
You buy you boat in a foreign country. First you have to register the vessel in your country with your name. Since the boat is outside of your country, you have no taxes to pay. (double-check with your custom)
Once you return.
You want to sale the boat. Sale it in a foreign country, still no taxes to pay.
You want to keep you boat. Once your boat will be in the waters of your country, you will have to pay VAT.
Hope this helps a little.