Not too sure about the odds being 'pretty favorable' (unless I am super unlucky).
Decided to get my last 3 dragons (and only 3 items I have left).
I have done 220 spins (110k) and only gotten one so far...
My total so far on this capsule is $278,500 or 557 spins.
Hard to ballpark the odds since at the start I got a lot of items in a low amount of spins relatively speaking but that's due to there being more items to have won but now with 3 maybe we can better an estimate.