Hi Mike,
Usually the spin sheet drops right down on to the drum. The drum width accommodates it nicely, but it is important
to keep the line in the jaws of the pole on the foredeck and also tighten the guy at that point and it shouldn’t fall off of that.
(By the way, this should be done after the jib has been unfurled)
Also, we epoxied a 1” strip of Starboard under the rail to secure the Harken jib track to, I know you could probably figure out a way to secure a strip of fiberglass rail in there too if you’re so inclined, I think that would make a better bond if you have those skills.
Best wishes, Rick