To be completly honest I haven't used tigerhair in a very long time it just dosen't finish right. If you need that much bondo you should do a little more hamer&dolly or pulling. I've seen bondo on cars over 1" thivk thats just lazy and can fall out. If your going to do the job try as hard as you can to do it right. Keep the filler as thin as you can, and use a long board