The Birkin you might get well above retail depending on size, leather, color. The Jypsiere I don't think so.
I don't think this is verboten to discuss -commissions are public for the most part - - eBay will take the least commission and has a program specifically for luxury bags. However, Ann's Fabulous Finds and TheRealReal won't be that far off eBay's take, and you don't have to do all the work and stress out about eBay scams.
Fashionphile will give you a quote - in my experience their offers are not great but with a new Birkin in box it is worth trying.
Take a look at the reseller thread as it includes seller experiences as well as buyer experiences. Good luck.