r60 cellulose in mine no sag, in 8 years i have done 8000+ attics and no sag complaints..glass is lighter but its crap and batts dont seal near as well
agreed cellulose is def needed to be installed correct, with water mixture because it is a settled blown depth this way, and u can get cheated easier with glass. and ur right half value lost 20 and below! 1000 sq here we do it for 460 and that is cheaper than average by a mile, and fiberglass isn...
1300?