I've probably earned 30-40, between what's in my inventory and what I've spent, so I don't rush off to Odin fates unless I happen to get an invite and I'm free. Odin fates are what S Ranks should have been, he's more of a Z Rank. There's more time to get into a party (which is important for credit and raises due to big AOE). Don't forget to reset your home point to the aetheryte near him, I always forget until too late.

I would personally recommend spending first 5 mantles on Slepnir Chocobo Barding (not same as mount which is cash shop). And find 7 others who want to grind out Odin trial until everyone has everything they want. All you need is 5 others, since I'm on the same server and wouldn't mind doing it to get helm for my DoW classes. It's a decent alternative to the latter EX Primals for people who haven't unlocked them I suppose.