Disributed Platfroms become heterogeneous in more and more domains, as heterogeneous computing (HC) onto grids or reconfigurable factories in industry. For production grids and factories, it is mandatory to control and optimize the economic cost of a such platfroms regarding performance objectives. We present in this paper a study which purpose is to optimize the size of such environments depending on the workflow to esecute or product to realize. the target platfroms are either micro-factories, sixed to manufacture products at the micrometric scale, or the heterogeneous computing domain where the key point is to reserve processors of an execution platfrom onto a grid to compute workflow like medical imaging applications. Thanks to the sizing of the platfrom ,optimal or not,scheduling a workflow in HC environment or a production in the micro-factory is easy because the size of the platfrom already takes the performance costraints into account. In this paper ; we presents general result on the platfrom size optimization. Numerical results are also presented to ilustrate 3 cases of our study.