That's the way it's typically done. I used Cableorganizer.com's chrome braided EBS over all my external wires and then put their clear heat shrink over it.
That's the regulator wire following the curve of the engine case.
Not really necessary, but just something I thought I'd do. Overkill.
If I hadn't done that, I'd probably at least make sure the sections where the regulator wire enters and leaves the seat post tube had some heat shrink protecting the wires at those points. You can get plain black heat shrink at Harbor Freight in 4 foot lengths at a good price in a variety of sizes.