Composite Shims on Short Retaining Wall

Question

Would there be an issue with using composite shims to help level one layer of block on top of another?
Other possible relevant info

• I am using 6in x 12in retaining wall block.
• Max height is 3 blocks tall (plus capstone)
• Using 3/4 in agg to backfill behind the block, inside the block cavity, and under the 1st layer of block.
• Ground and 3/4 in agg stone are tamped and leveled prior to block placement
• Capstones will be secured using landscape block adhesive.
• I will probably squirt some landscape block adhesive into any gaps created around the shims.
• I would expect to use shims on maybe 3 bricks where it's been tough to transition from one layer to another due to the hill slope.
• Checking to make sure the shims do not cause any block wiggle once installed.

Answer 1

These blocks are designed to be installed loose, and that tree's roots are going to win any disagreement they have with them. trying to make a permanent structure from these semi-permanent retaining blocks seems futile, especially in this location.

plastic, fibre-cement, or slate (etc) shims will not cause any significant weakening of the wall.