From the ebay listing: AWG 30 (0.26mm core) silver plated copper wire with heat resistant Kynar insulation.
What is the impedance? Standard 30awg is .1ohm per foot. You need to know this to calculate the length of wire you'll need at achieve the wattage you want.
I do like the idea of threading the resistance wire through a mesh liner - I even bought a cheap windbreaker for that purpose. Next time. It's still easier to make simple repairs to my existing jacket liner since I learned to sew the wires on so they are visible and easily accessible.
Keep in mind that sooner or later you will need to make repairs, maybe even while out on a long trip.