I'm looking to collect those toven cookies, so:
5k Plat: 1 Toven Cookie (I'd prefer to buy these in bulk, doing trades 1 at a time is a pain in the ass)
1 flawless Scale: 60 Toven Cookies
I large devil scale: 30 Toven Cookies
I large stone: 20 Toven cookies
Every other large: Meh, whatever - like 5-10 or something.
I think those seem fair - do it!