You can apply for a NON-O if you have a monthly income from abroad, or sufficient funds in your Bankaccount. But in order to have a work permit, you need a NON-B visa
Usually next day collection, apart if there is a weekend or holidays. If there would be a problem, you still would get your passport back by the next working day and you'd need to re-apply with whatever was missing before.
in Chulia Street. He provides an excellent and professional service since decades. No point doing it by yourself, you'd pay the same on taxi or bus fares running back and forth to the embassy.