In the development of some real-time embedded applications, especially systems-on-chip, an efficient use of RAM memory is as important as the effective scheduling of the computation resources. The design problem is to find a schedulable solution that fits within the memory budget. In a real-time concurrent system, preemption plays an important role in the exploration of these tradeoffs. Several schemes, including preemption thresholds and non-preemption groups, have been developed to improve schedulability and saving stack memory space by selectively disabling preemption. However, the design synthesis problem for such systems and protocols is still an open problem. We target at the efficient assignment of the scheduling parameters for systems scheduled according to these policies in several cases of practical interest, including those that are compliant with automotive standards.