You are representing a landlord negotiating a 15-year Triple Net (NNN) lease with a Fortune 500 retail tenant for a newly built 20,000 sq ft space. The tenant is pushing for a base rent reduction in exchange for a longer renewal option and a cap on structural expenses. Draft a counter-proposal that protects the landlord's yield. Specifically, address the following points: 1) Establish a base rent with 2.5% annual escalations. 2) Define the 'structural expenses' clearly to minimize landlord exposure. 3) Propose a percentage rent clause should the tenant's gross sales exceed a specific breakpoint. 4) Justify your strategy in terms of long-term asset appreciation and risk mitigation.