That seems reasonably simple
. Might just go with this approach. So, to again confirm,
NO changes were done to the rear mounting of the front leaf?
This is what I plan to do. Please check if I am on correct path:
1. Use STOCK rear leafs. Remove the over load leaf & add 1 or 2 front leafs to the bottom of the pack.
2. Use the rear mount AS IS.
3. This will move the axle by 1.5" in front. For that use a spacer for front drive shaft. (No changes required ANY WHERE else)
4. Use the folding shackle as you have outlined.
Is that all?
This method i like as this allows you to go back to stock also. No alteration that can't be reversed :-)