Best deals on slot loss reimbursement?

[kirbyk1]

I think there are several promotions that offer to soften your slot machine losses with additional free play but there are several questions: (1) do any apply to existing members rather than just for new members, (2) given that my annual visit is only 5 days long, which promotions give the most back quickly,and (3) if you had just one to do, which one would you choose as a new member - soninlaw will have first trip in March.