Hi Tango I make my own muesli in bulk (as there are 6 of us) but I just add to a big mixing bowl.....
1 to 1.5 packet of rolled oats
1/2 packet of oat bran
1/2 packet of all bran (or equivalent)
1/s small packet of dates
1/2 small packet of apricots
2 handfuls of sultanas
2 handfuls of raisins
1 small packet of slivered almonds
1 handful of pepita's
1 handful of sunflower kernels (more if you want)
mix them altogether...once you have mixed it you can see if you have enough fruit in it and add some more if you like or you may need to add more oats......you can add what ever you like to it or take away stuff that you don't...you can try adding other dried fruit to it as well for a different combo.....
hope this is a help or at least something you can build on to make it how you would like.