I replaced the valve cover two years ago --and so far so good (knock on wood)--

I followed two of the links you already have there; the first one (full post) was quite helpful and had several tricks / recommendations already; from what I can recall:

1. take time to make as much space as possible in the back of the engine, I pulled up the cables with a bungee cord to keep them out the way when removing/installing cover; the bolts are the back are very hard to reach and limited visibility so the added space was key. There is a bracket that gets in the way, I read it in the first post I was using as reference but did not realize it importance until encounter the same issue.

2. I vacuumed the engine thoroughly before removing the cover; tried to remove any dust/dirt that could then drop inside the engine

3. I used ziplock bags to store the high-pressure fuel rails and marked them individually

4. the party ballon trick is good but they tend to fell so I used electric caps (twist-on connectors) to keep then tight (will try to post pictures later)

5. When I did the valve cover, took the time to change the Oil Filter Housing Gasket as well. It was completely flat.

6. Clean the surface throrughly before putting the new one.

7. I see you plan to buy the torque wrench; I did buy as well as read everywhere that properly torquing the valve cover is key, I printed the sequence for reference as it is complex. Also bought the crow feet.

Good Luck !

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E70 - 3.0si & F10 - 535ix
Previous Cars:
E34 - 525i, E39 - 530i, E60 - 530i