The server sets client id in the player function that was given on the client when he ent_created the entity on the server...
After the server sets this client id , he sends it to all clients just before he sets my.nosend on.
Later , you go thru the list of clients , check if this ID is the same as the current entity on the list...If it is , send_var_to I never used send string instructions btw :P

What I didnt mention was , on the client , when a client receives a var , event_var is activated in the client event function (or was it another event name? I forgot already )
If event var has been received , and the updating arrays first var is empty , calls a function that manages the updating array and distributes it to the entitys skills. After that it sets the updating array to 0. This will enshure , that , if you send another var , the updating vars Client ID is 0 , so , no updating will occur.

You've got it right , I just wanned to explain it better to avoid confusion
fastlane , I tought you used a plugin :P ?