I'm planning on making my first mechanical box mod. One problem I've come across is the switch. Most of the switches I see are at max 5 amp rated, but I would like to be able to use the mod for up to 30 amps, with 20 amps being my minimum. Any help with this? Also, what do most people do for a battery pack/holder? I was planning on using 2 18650 batteries in parallel.