Unless I'm mistaken..Ebay doesn't really implement a 'default' return policy per se'. For sellers using ebay's Sell-your-item form... the return policy specification is made available for each individual listing created (at the time of creation). With Auctiva however, using the 'checkout options' when creating listings...we have the ability to specify a return policy as well (as you probably know). I believe this so-called 'checkout option / return-policy' specifier is passed thru to ebay's internal 'listing parser' (my terminology) for each ebay listing procedure-call generated as a function of Auctiva's listing submission process. And since we have the ability to use the 'checkout-options' and 'create-similar-listing' features in Auctiva...then we have in practical effect, a mechanism for a pseudo-default return policy specification.
Since your question indicates a need for specifying a return policy differently for some items, then assuming you don't want to 'revise' posted ebay listings (or use ebay's sell-your-item form) then the change would need to be done locally with Auctiva's 'checkout-options' > 'return-policy' feature for each Auctiva listing created here prior to submission for posting on Ebay.
Hope this helps.
