The issue of RTR (C) or RTR (P) will be of max of 20 yrs or Till the validity of ur foreign FRTOL/CPL.. validty will depend on which ever is earlier....u just need to fill up the form and will get RTR(P).
If u have CPL for 5 yrs but FRTOL for 20 yrs u wil get RTR(P) on validity of CPL...ie ur RTR(P) will be valid till ur CPL date.But if u have CPL valid for lifetime but FRTOL for 5 yrs u will RTR(P) on valdity of FRTOL.
If u have cleared Part 1 ....ur RTR(C) will have validity till ur FRTOL date.
If u have cleared Both Part 1&2....u have option of 20 yrs or lifetime...and will get RTR(A).