RLW is similar to RTOW in that the most limiting of a number of considerations dictates the weight restriction on the day. It's up to the operator/commander as to how the sums might be done.
Looking specifically to your question, the limits also include landing climb gradient (AEO, landing flap, gear down).
If the company does the work, then the ops manual will have the final output including all the limitations. If the pilot does it, then the AFM will lead you through the step A-B-C process in a manner similar to figuring the RTOW.