Solid call on the grosgrain + Aquaseal for Tyvek-I’ve botched a couple mods without it, and yeah, granite edges turn it to confetti fast. Did the Crazy Creek DIY on a generic 4lb chair last summer (pre-taped seams with 2oz silnylon thread), dropped it to 2.8lbs total. Survived 40mi in the Winds with zero tears, but it’s stiff as hell in sub-40F-no flex for long sits.
For Mac Lite Trek specifically (confirmed 6.6lbs shipped weight via their site, 600D poly oxford), Tyvek swap feasibility is meh: factory frame geometry is wonky for taut pitch, and those mesh pockets rip easy under 250lb load. Better hack: strip the pockets entirely (save 4oz), reinforce leg joints with carbon fiber tubes (epoxy in ¼″ sections, 8oz gain but 2x stability on talus).
Helinox Chair Two still crushes at 2.1lbs for 2-person width if you’re soloing tall. Pics of my reinforced Trek lash-up on an Osprey Aether [link placeholder]: bungeed side compression straps, zero sway at 30mph gusts.
JMT test incoming-who’s got polycro or Dyneema mods holding 300lb+? Durability data? 🏞️