TOPIC: Evinrude controller and cables

Today I swapped the Evinrude controller into my Glasspar. I'll need to buy some shorter control cables. I have a 1984 controller in great shape, and I'm wondering, should I open it up and lube the internals, or go with the "if it ain't broke don't fix it" method? It's a freshwater setup and operates smoothly. Also, any tips on changing the cables would be a help. how to remove the old ones and attach the new at the controller, how to calculate correct length, etc. Seems like I've read that you should allow enough extra length to make a large loop at the motor end?
The cables I have are Teleflex #479 CC 20512 C84.