Hi as a solar pv specialist working for Hilti i would not advice you to go down this route for many reasons
1. Any commerical installation should have wind and snow loads etc done for the project including potentially design loads - which we can do
2. Unistrut would be far to heavy for the roof as its made form steel
3. Convenional strut is galvanised and will rust - hot dipped galvanised in warranted for outdoor use
4. Unistrut has never been tested under a solar enviroment and would be to risky to use in the uk, you should be using an aluminium mounting rail system
