No problems with BIAB.
I've often done a full boil with PM kits. Most of the time, I don't even both adjusting the bittering hops. If you are concerned, using 2/3rds of the recipe's bittering add is a good place to start.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
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