The NX-x50 Owners Manual says
Hammock storage, care, sealing
...Do not seal your rain fly unless you find a reason to do so. Seams can
lose integrity from being jerked or pulled over time. If you find a spot that
needs sealing, use Sil-Net by Mcnett, or another product that is formulated
for sil-nylon fabrics.

Is there any reason to seam seal a new XL or Vertex tarp? Thanks