Hi Jep and welcome,
Officially the tyre pressures are 1.8 bar front and 2 bar rear. (4.2 bar for the spare) I have to admit though that I run mine at a bit over 30psi
On the unzip, it does say in the handbook to un-zip and a tip is to unclip at the front and knock the roof out of it's locked position to give a bit of slack on the zip.
It's difficult to give values for stuff particularly something that can be made fairly easily. You can post it on the bits for sale and see what the response is and make your mind up from that.
Have fun in your Beat
If it ain't broke, take it apart and see how it works