It really is impossible to predict your base. A serbian guy friend of mine got Belgrade, but you cannot be sure.
Be ready to go to Kutaisi or some romanian base, and you won't be disappointed.
Basic salary changes depending on the local taxes, but the final net numbers are similar for every base. Some bases are flying more than others, and end up with more money (eg Gdansk).
They are desperate for Captains, if you do well you can expect upgrade as soon as you have the requirements (500 hours in the company if I remember well).
In the summer you can expect anything from 50 to 100 hours. At the end of the year you will have maximum hours or close.