Installing add a leafs in SR5 Double Cab Short Bed

So I installed a leveling kit with the blocks in the rear, now the rear has settled creating a minor reverse rake. I contacted the manufacturer and they sent me out a pair of add a leafs plus the drop down shims for the driveline.
So here's the question, from all I've read the add a leaf should be mounted between the lower overload flat spring and the leaf pack right? The three leafs above are held together by rubber mounted clamps so that doesn't look like a good option?
The leaf pack will have to be removed for the install I'm sure, just asking for help from anyone who has done it, thanks in advance for the help!