I agree with Claire, if I am convo'd asking about shipping times or such, I suggest the various methods and include the priority and express mail estimated delivery times and costs as quoted by USPS.COM
Once the buyer tells me which way they want to go, I then adjust the postage for that amount, put it up as a RESERVE LISTING FOR ____ and the purchase proceeds. I have done that many times.
How does that effect relevancy, Brandon? I am interested in that, as I wouldn't have suspected it changed a thing other than the shipping cost to the buyer.