We purchased a 32x16 doughboy desert spring and couldn’t find an installer so hired landscape company for the ground prep. Tan in to issues with drainage so they added French drains etc and then put down geo -textural landscape fabric and crushed 5/8 minus gravel, compacted over our clay soil. The company did the side supports and pressure pads but all of the ground is leveled to the height of the side support/pressure pad. We went to install the bottom rails and realized they will be floating! We have masonry sand ready to spread and level over the gravel and under the liner but not sure the best option for leveling around the oval bottom rails? Finer compacted gravel?