UPDATE STATUS
Remote client copy is through RFC and it will not create a transport request
Transaction Code: SCC9.
Client Export is via transport. When you do a client export the system will create more than one transport request depends on the profile you select
Transaction Code: SCC8. Client Export will create cofile and data file in your source system /usr/sap/trans data and cofile directory. Copy the transport requests to your target system(Data file and Cofile). These transport you need to import into the target client using tp addtobuffer and tp import command, after the import you need to run transaction - SCC7 in target system, which will perform the post import activities for the client import.
The best method for the client copy is Client Export and import process compare to RFC. RFC process works fine for small amount of data copies and depends on the profile you are going to choose for the copies. For large db's better go for export import and file split options if you are n unix 10.20. Unix has file limitations for 2 gb.
A large client copy with export and import post processing took 4 days for the export, 14 days for
the import on unix 10.20 for 68 gb of data.
Some times user may get an informative message "Maximum number of sessions reached". You should alter the parameter rdisp/max_alt_modes for this purpose. Take transaction RZ10 (profile edit). Take instance profile. Then take the option Extended maintenance. Its default value is 6. Restart the instance.