Just looking at pics it seems to me that the yellow bellies have a wider white (sometimes with mottled yellow) belly. Yours barley has the dark excluded from the big scale down the middle. Looking at Graziani's excellent picture you will see that the dark checkerboards are mostly excluded from all three belly scales. Also yours has rather large (normal) checks and not the small broken up checks congregated at the edge of the yellow belly pics I've seen.
I'm a little unclear of what the sides should look like but perhaps the bands starting to widen again down near the belly with fading in the middle is something to look for. I've got even less of a feel for if there are dorsal pattern traits or what they should look like.