It really depends on her strength climbing. There is much more of it at Roth than I thought going into it, seeing as it is a world record course. Greding is the worst of it, which is a sneaky beast. That may be the only Hill where it really would matter, especially on the second lap, but 28 should suffice. The only other Hill of note is Solar, but that's not too steep, just long, but the crowd pulls you right up it. Tell your friend she is about to embark on the greatest experience of her life!