There are only two holes to attach things to at the bow. The upper one is for the forestay, right? And the lower one is to attach the tack of the jib or genoa, correct? Where, then, would I affix this additional line? Of course, I can just use that line that is currently there, but to what do I affix it?I'm unclear what sheet your refering to.
Do you mean the thin one that runs up to the bow? It would be used to furl the sail.
Then no you don't need it.
However... Before i got a furler on one of my boats I used a thin line to go from the cockpit to the top of the genoa/ jib I put it through every other hank. I ran it along hte cabin top just ike the furling line. I used this pull the sail down from the cockpit.
It worked fine. Just get a 2" SS ring and tie it to the bow ware the for-stay attaches. It acts as a turning block.