Last year I had cellulose insulation pumped into the walls of my basement suite. The contractor drilled many small holes in each wall cavity, but didn't really specify how these are repaired. I have some drywall tape, spackle and the round drywall pieces that were removed but when I place the tape over the holes the area is still pretty hallow. I could also put something behind each hole to support the pieces, but with 50+ holes to repair this would be extremely time consuming. Is there an easier way?