In preparation for the first simulation of a real globular cluster with a few 105 particles and several Gyr of evolution, which will be made possible by the advent of the new GRAPE-8, the MODEST community encharged our working group (WG-9) to provide all of the needed observational constrains. The selected clusters for this experiment were NGC 6121 (M 4) and NGC 6397. We present the status of the project.