I don't like going much above 20x d+b on manual offers, but in order to tell if a bonus is worth doing you should just base it on the expected profit and the hourly rate that works out at for your chosen stake. What are you willing to work for?
e.g. a 100/100 bonus with
BJ allowed will usually stay profitable right up until around 125x d+b, but if you're getting above 100x you'd probably be better off picking up coins in the street
