Evaluation board (EVB) assemblies or stacks utilized in tuning electronic modules are disclosed, as are methods for tuning such modules. In embodiments, the module testing assembly includes an EVB and an EVB baseplate. The EVB includes, in turn, an EVB through-port extending from a first EVB side to a second, opposing EVB side; and a module mount region on the first EVB side and extending about a periphery of the EVB through-port. The module mount region is shaped and sized to accommodate installation of a sample electronic module provided in a partially-completed, pre-encapsulated state fabricated in accordance with a separate thermal path electronic module design. A baseplate through-port combines with the EVB through-port to form a tuning access tunnel providing physical access to circuit components of the sample electronic module through the EVB baseplate from the second EVB side when the sample electronic module is installed on the module mount region.