I think I know the answer already but just wanted a confirmation. I am having an issue finding the answer in the book, but I am running a tournament where the time control is G30;+15. Since this is dual rated, I assume notation is required till less than 5 minutes remaining?

Yepâ€“because the base time control is 30 + 15 = 45. For all rated games: If the total is 30 or more notation is required. If the total is less than 30 then notation is not required.

You can look at it this way. A dual-rated tournament is nothing more than a regular-rated tournament which happens to be also rated under the quick system. Since it is regular-rated, regular-rated rules apply.