Yuchai doesn't make any bolt-on snow accessories that I know of, however there are some shoes at Northern Tool that you could easily adapt, but you would still have to use some finesse with the blade on loose gravel.
My suggestion would be to mount a pair of heavy duty pneumatic swivel casters to the backside of the blade and make them manually adjustable for height with jack screws. Then you can use the dozer's float position with no worries about gouging the gravel.