The HH 70D Hex is a Polyurethane coated tarp rather than sil coated. You want Seam Grip rather than sil of any sort to patch it. LINK
If the holes are smaller than a dime then just put the tarp over wax paper and slather on some Seam Grip and let cure. Sil may stick to start but would peal with use and time, Seam Grip will hold solid even over smaller holes for year.
A second option would be to just cover both sides of the holes with a small patch of Tenacious Tape (link)