A great point. Particularly for cast shooters where you may have one load doing a bit over 1000fps, another in the 14-1600fps and a 1900fps hunting load. With the Williams or Lyman 66 you can record the rear sight elevation and just dial it in for shooting that load. The Skinner is set for one load requiring anything else to be hold over/under estimations.
Yes the skinner has that restriction however the Lyman and Williams side mounted options are great - this is a Lyman 66 on my Winchester 1894 30-30, ejection is unaffected: