It's worth remembering a couple of points about how courts handle "MO" and 'similar fact' evidence
Germany has different rules of evidence as it doesn't use juries, but we can still make analogies. As a general rule, similar fact evidence is not admissible in common law countries. Ditto 'propensity' reasoning is not allowed i.e. he is the kind of person who would do a murder. You have to offer evidence that directly proves facts at issue - not generic profiles or character types.
So what is allowed?
In England, the rapes on video would likely be allowed as evidence in the HB case, due to uniquely similar modes (whipping, style of dress etc). i don't think they offer MO evidence in the MM case as we have no evidence as to the MO in the MM case. In fact the MO appears different. (short time frame vs extended attacks).
if it could be proven CB did burglaries at the OC that might well be relevant.
But again one of the problems in this case is things we think we know are either
1. Not from the prosecutor but 'reporting' from journalists of unknown quality
2. Hearsay evidence recounted to above journalists
For instance the supposed SIM card from OC 4 would be a huge piece of evidence if it actually exists.
Ditto 'Das Buch' - posters place importance on it, but does it exist?