First of all, I'm not entirely convinced that is a real storm jib... most have a very heavy cloth, triple stitching .... It could just be a 80/90 percent working jib that the p.o. wanted to use as a "jib top" or "yankee" by going full hoist (except that would be unusual on a small trailerable production boat.
It could simply be a sail he was given, or got a good deal on, and just wanted to use it without installing new or adjustable fairleads.
That said, I'm not sure why you would put a pendant between the halyard and the headboard for tacking it at deck level. Is the halyard too short for that?
Maybe the previous owner simply wanted to get the sail clear of the lifelines even though the clew is cut high enough, or had a dinghy on the foredeck... who knows.
I would suggest adjusting the sail hoist to match the proper sheet angle to the fairlead... then build another pendant to fit .... then you have the correct hoist for the lead position.... or... install another set of fairleads.
Bisect the angle at the clew made by the foot and leech to get your neutral sheet lead angle.
Use the sail on windy days or when you're single handing and don't feel like messing with a genoa. Play around with it, with or without the pendant, and see what works best for you... maybe your question will answer itself when you try to use the sail.