I have an award ticket booked DTW-FRA in F on LH using UA miles continuing on LH J to MUC, finally SA J to JNB. This is for a church mission trip so I am interested in maximizing my free baggage allowance. The rules are not clear to me with the F, J and mix of carriers. Edit for clarification: the itinerary is DTW-JNB - the other parts are layovers not stopovers.

How many bags of what size can I take? I am UA gold if that helps.