Level Best or Dual Dozer?? Need Help

I am in the market (very soon) for a laser controlled grading box or blade for my Cat 289D. My question is, does anybody have experience with either one of these brands or both, and how do you like them, advantages, disadvantages, etc. I note the wheels are behind the box on the Dual Dozer and can see where this would be helpful, but not sure how critical that is. Does Cat make anything similar? My Cat salesman never gets back to me.



One other question, we have a job coming up that is about 13,000 sq.ft. of floor to grade for concrete. Approximately, how long should this take if the crushed gravel is roughed in place?



Thanks for any responses.

Level Best or Dual Dozer?? Need Help