Not trying to be a jerk, but you can tell us better than we can tell you. Either there is enough room for the shackle to compress(fold) without bottoming against the spring/frame when the tire is at full stuff or there isn't. Put the rear tire up on a rock, etc with it stuffed all the way up in the wheel well and the axle on the bump stop and see if there is still room for the shackle to compress a little more without binding. If so then you are good in that regard.
What I WOULD be concerned about is the extreme length of the shackle. It gives the leaf spring a ton of leverage to try and twist the frame end shackle mount off of the frame either when the suspension is twisted up or if street driven when cornering. In other words the shackle is acting like a breaker bar for the spring to use to twist the frame side shackle mount off of the frame. I would expect it to flex great. Especially with no cross brace in the shackle, but I would be worried about the lack of side to side stability on the street and I would keep a close watch on that un-braced upper shackle mount for cracks. I bet if you opened the rear hatch, grabbed a hold of the hatch opening with your hands, and pushed the spring eye sideways with your foot, it moves pretty far.
Then again...if it has been working fine for you, for long enough, then I might just be overly cautious.