I would never do that for the front, on an uphill climb, my front suspension already unloads real bad, and with a reversed shackle the pinion begins to crawl downward. With a pivoting shackle mount, you would loose almost all weight on the front on an uphill and you pinion would be pointing at the ground.
The only reason I did it on the rear was I was hardly getting any downtravel, and the chevies are still a little too long for the pushed forward hanger so my shackle angle sucked at ride height so I didn't get much compression either.