(You need to specify if you are going to use a 'triangle' style skeg vs 'fin' - there are some of the latter style.)

The problem with the 'fin' (high aspect) skeg style IMO is that the lateral plane (side area) is almost unchanged whether the fin is 'full down' or 'half down' - and skegs (which are fully immersed in most conditions) depend on side area to do their job.

High aspect skegs are also much more fragile - not all my 'encounters' with rocks' are straightforward 'head-on collisions' where I paddle over a rock; sometimes the boat can be shoved sideways by a wave while being inattentive (chatting, rescue, having a snack, listening to an instructor) near rocks. Using plastic (Starboard) for the skeg -like most commercial boats do- is something to consider. Skegs are IMO more vulnerable than rudders, since most good rudders can 'kick up' easily.

BTW, regulating the amount of friction in a cable system is tricky, as you want to be able to retract the skeg with 'less than ape-man' force but don't want the skeg dropping down on its own. The cable size and tubing size matter, as well as the 'throw' in the cable (length change in cable to deploy/retract).