Well, can't give you an air tight legal opinion, but...
I designed and built my own commercial wall.
Drop me an e-mail address by pm and I'll send you a copy of the EU standard on PDF.
Insurance would be in the ball park of the operator. Your liability would be restricted to (usually) 10 x the fee you charged, so no fee, no liability (not a legal opinion).
EXCEPT! In the case of criminal negligence! Nothing can indemnify you against that.
If you follow the standards, between you, ensure that the materials are up to scratch and fixings adequate and installed 100% as per manufacturers specs, you should be safe.
Any engineering background?
I like to use Autodesk Force Effect to calc the statics within each section of structure, using the parameters laid out in the specs (Autodesk do a great tutorial for it). It's available for iCrap in the App Store, not sure about Android, but I guess so.
A very useful 3d modelling tool, open source, is SketchUp. Easy to master even without previous CAD experience.
Just do it.