Taipan Factory regulator

Good evening I was curious if anyone knew the minimum bar setting for a factory regulator? Also, when I disassembled mine the washers were not in the Ernest Rowe layout. Concave out with 7 pairs in between. Can these washers be stacked different to further adjust the regulator. I currently have it bottomed out and the washers stacked per Ernest and only get down to about 120 bar. Any ideas are greatly appreciated. I am trying to get a backyard short range setup .