To avoid lines, do I need to buy advance ticket to enter St Peters? Know I need advance ticket for entering Sistine Chapel, but if I also pay for a tour of Chapel-- do I avoid more lines? Looks to me that a ticket to Chapel, does not move u to head of line, which some folks hv said requires being part of a small tour. What do I do to best avoid the lines at both places? I'll be there early May, will that be high tourism time in Vatican City? Recommendations for who to get tickets/tours from?