If my high school physics doesn't fail me, as long as you have the same amount of work to do (pulling the clutch apart against the springs), you can only trade off force vs distance. No matter which method you chose, wire or hydraulics, the only way to decrease the force of the pull is to increase the distance you need to pull, which is a problem if she has small hands.
Granted, high school physics doesn't take friction into consideration - if there's considerable friction within the clutch cable which causes the stress, rather than the force of the clutch springs, you may gain on moving to a hydraulic clutch. But if that were the case, your first step would be to lubricate (or replace) the cable. A properly maintained clutch cable has very little friction and the force you feel on the lever is purely from the springs.
2019 390 Duke