Savenellis should hold their value better than many mid-level pipes with less established names.
I'd start them at 30% to 40% of what you paid retail and hope they bid up beyond 50%. Since
they're relatively new, and most of them are likely still available new, most buyers are going to
compare the price to the current item directly. With older pipes, people can't place the price
as exactly, and older pipes in good shape may gain a little in collectible status. You can't get one
of those any more. This is a fine art, and I'm not experienced, but that's my best instinct.