Keep in mind the wine is balanced to be sweet, so the acid level is likely to be higher. Leaving the sugar out may produce a wine that is too acidic. This depends on your tastes as some folks like acidic wines.
I suggest you bench test -- after bulk aging 3-6 months, draw 4 half glasses. Leave one dry, and backsweeten the others with small, varying amounts of syrup, then taste test. Keep in mind that you do not have to use the full F-pack. You may like 1/4, 1/2, or all of it.
I greatly prefer dry wines, and last fall purchased a few bottles of Vignoles from a Finger Lakes NY winery that I habitually order from. When I got the bottles the back label said the wine is sweet. Well ... @^*%!!!
Oh, well, got the bottles so I tried one. It tasted off-dry, not sweet, because the acid level is really high. The wine is VERY well balanced.
A wine's residual sugar and how sweet it tastes are directly affected by the acid level. You may find that backsweetening the wine will not have the effect you expect.