I'm going to take my car to get an oil change at the Honda dealer and I'm a little worried of what I've heard of the experiences other people have had with dealers in oil changes. Some say they get charged for 5 quarts, when that's really over how much they're really supposed to get in their car. Others say to ask for the leftover oil (that there should be at least a little under half a bottle).

I have a 07 Honda Accord V6 45k miles
I don't have the owners manual b/c the person I bought it from had lost it.
How many quarts of oil do I need to make sure my car received before paying after service?
I want good quality oil for my vehicle, is there anything specific I should ask/demand for?
Do they use synthetic oil, should I tell them to use synthetic oil?
Any other tips with dealing with honda dealer for maintenance?
I've had horrible experiences with other mechanics when I've gone before, so I feel Honda is my only option since I don't know how to do it myself. :\
***Should I ask for Mobil 5W20 synthetic yes or no?