Ability to specify SAAS runner instance size in components

For some of our larger opentofu deployments, I'm looking for the ability to be able to specify a larger instance for the plan and apply to execute in. It appears that the saas-linux-small-amd64 is the defaullt, but I was looking to be able to specify if possible to saas-linux-medium-amd64.

I tried passing these as tags into the component and also by setting a global variable of

variables:
  OPENTOFU_COMPONENT_IMAGE_BUILD_RUNNER_TAG: 'saas-linux-medium-amd64' 

both don't seem to have an influence on the runner. Any guidance or advise is appreciated.