Something to consider, my cook system consists of a Vargo BOT 700 (138g), 100g gas canister (200g), and Primus Micron Piezo (96g) is 140g lighter, more compact, and capable of melting more water than a thermos. You can also achieve the same system for less money and less weight using a Toaks 750ml pot, BRS 3000 stove, and mini BIC lighter. There is the added boiling time and needing a sheltered area to consider, but I don’t think these are insurmountable for most people and might provided a welcome rest opportunity.