/sline in a custom window selects the specified line.
See /help /aline and look down 5 lines
Please note that I tried to make an @Window of my music, and while I don't remember how many files the @window did hold, I'm quite sure it was well under the 3000 mark.
By adding files/lines to the @Window that exceed the limit of the window, the top line(s) get lost.