Referenced model workspace initialization

I have a project that requires concurrent execution. Because of this I must use referenced models. When I switched my pre-existing subsystems to referenced models, I observed input dimension issues for mask parameters. I believe I deduced that the problem was that I initialized the parameters in the model workspace to ‘1’ thus making the parameter a [1x1] variable. I wish to make the parameter of a size that is dictated by workspace variables. However, the menu will not let me input variables for the value or dimension fields. I do not wish for these variables to be tunable in any way…I just wish for their dimensions to be subject to initialization variables in the workspace at compile-time. At present, I can only hard-code them to static values.