i'm currently changing porridge from wagg hamster, gerbil, mouse much (i hate it)
but especially cause it would just be plain difficult having too have peggy and him on two different foods. Plus its not availible near me.
So i'm changing him onto harry hamster which i def reccommend but its your choice
I have no experience with pah muesli so i can't comment.
For the change over i started with 1/4 of table spoon just for a taster to see if he would eat it.
then half a table spoon and the same again the 3 rd time.
And now hes on one table spoon hh and 1 table spoon wagg.
will be doing 1 and a half tommorow and 2 the time after that
But porridge is a really good eater anyway and always cleans his bowl even the not so nice bits