id did mine the way i set it up as the older charger build with the belt round the alternator pulley cause them to fail early as poundy found out the way you have it set up in the last image if you put the bracket at the rear of the alternator the belt can go a different route and still do cover the pulley the other issue is the ac pipe on the astra with the straight run from charger to ac pump the belt would cut the ac pipe or water pipe before long
cs standard setup for the supercharger bracket with one pulley
i do like the evo bracket 🙂 tried and tested for 1000's of miles now
