Danish wood oil. A few quid and a few minutes when you feel like it - maybe 2 or 3 times a year. I used this on all my external woodwork 2 yrs ago, cockpit seats/ sole, strakes and handrails. The boat has not been lifted out since and is well used on E coast Scotland where we have a lot of weather, and rubbing ! Couldn't be easier and leaves lots of time for a huge variey of other distractions from sailing.
Yopu could varnish, then put some brass or bronze or stainless "D" strip down the rubbing strakes, that would protect them, however I stand by my first post, oil and sail!