Marrakai,

My only thoughts would be that with the length the rear site would act much more like a peep sight than a ghostring. The added length is surely going to make it more likely that the rear sight/ghost ring doesn't simply "disappear" the way it should. The reason I say this is because unless you have a significant back bore you will still be seeing the sides of the elongated tube and this will have the effect of making it more prominent in your vision and much more like a peep sight.

Just my thoughts. Though I like the look of the sight you drew up.

Bill