As a general rule for tournaments you have to use the game default optional rules, the optional rules recomended in the scenario, AND you can agree any adition with your oponents.
In this scenario that is: default rules, plus explicit supply AND you can agree any other optional rule with your oponent.
Of course, Volcano Man's, or other designers', Alt scenarios have their own default optional rules. VM's (the Alt scenarios most used here) default optional rules for his scenarios are explained at Theblitz here:
https://www.theblitz.club/message_boards...?tid=38745
Alt scenarios will be played using the optional rules recomended by his designer, AND, of course, any other optional rule that you agree with your oponent.
Regards.