Fiberglass is almost as dangerous as asbestos if it becomes airborne. Even if it works the best.
I would think that the cellulose would be safer even if the R factor is less.
You have to consider whatever you use may come threw cooks and crannies, like electrical outlets and the such.
I would use cellulose insulation, and maybe put more to reach the R factor that you want.
That is just what I would do in my house, I am no expert. But I do understand about Lung Caner.
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