Yes, if
halyard tension is too slack it can create problems. I have never experienced problems related to the halyard being too tensioned… that said it’s not a guitar string on my
boat.
The issue you may notice if it’s too slack is the halyard wraps partially around the forestay when
furling or unfurling the sail. On my
boat this messed with the
furler geometry enough to make it near impossible to furl the sail.
This can also happen if the halyard has too much stretch.
It’s possible to put an eye or “deflector fairleed” on the
mast to assist with the issues that I was having there.
Can’t speak to your specific boat or
furler. Do you have picture of the
mast top?