Ryvita/Weetabix in place of Scan Bran for Cakes?

Hi there

I have seen some recipes for cakes on the SW website that use scan bran. As I dont have any, is it OK to use Ryvita or even weetabix?

If so, is it a like for like amount of ryvitas, eg if the recipe is for 5 scan bran is it simply 5 ryvitas? Also how many weetabix would it work out as?

Thanks!