Could I get the Visa On Arrival at Lo Wu on Monday morning or noon time?

Hi, I am holding a Portuguese Passport and working in HK but I need to go to Shenzhen for an important client meeting on April 20, Monday late afternoon. If so, what documents I need to prepare for the VOA and can I have the full addrress in Lo Wu for obtaining the VOA? How long will it take and how many days I can stay in Shenzhen? Look forward to your favourable reply.