Drawing quires of a manuscript

I'm doing some testing for a font that might be useful for visualizing the physical structure of manuscripts (something like VCEditor).

Given a manuscript quire, the curve for a folio might need to descend above the baseline (in the image, each horizontal line corresponds to one line of text). I'll also create a vertical element to connect these curves, but I'm interested in whether a vertical position of ±6000 would be a problem (the font has 1000 units per eM).