73' B3 340 Duster pro touring build

76Orange,
I have seen cars with single leafs and four links in the back that drag and every car I have seen lifts in the front and rarely drops in the back.

Now I am no Engineer but I would think that no matter how you mount the lower control arm mount that the rear end is going to do what ever the springs and shocks let it do.
If you want a rear end that will not suck-up into the wheel well than get a stronger spring and a high quality shock to control the compression.

The way I see it everyone is going to have an opinion of what to do for your build, because they do not have to live with the decision. You have been do a great job on your build I say keep going with what you feel is right. Don't second guess your work, you may regret doing it their way later down the road.