>>26805393The shadow is very ambiguous. Reshiram and Zekrom share a number of design elements, intentionally so to further the comparissons between truth and ideals. That tail at the back of the shadow could be Reshiram's fluff as much as it could be Zekrom's spike, for one example.
There is no real canon pick between BW-BW2. Partly because it's your choice as to which dragon has more merit, and partly because truth and ideals are so ambiguous in and of themselves that it doesn't matter.
