We've done 4 bikes on a rack for years, its certainly an art
Especially tricksome with 4x full sussers!
We've got some extra extension arms from other bike racks, plus extra straps.
I now take a photo to remind me of the order and which way round first bike.
And we've never covered bikes, bar a bag over an old saddle that sucked up water.
Recommend very heavy duty chains & lock if you are to leave van unattended.
On the VW, you can also try and upgrade the struts to keep the tailgate up when bikes are on.
.. we now have 4x on a tilting towbar rack.
Post edited at 12:08