The biggest difference between the 2 brands (Naish & Duotone) that I could see & people mentioned were the structure of the 2 wind wings...The Duotone had a boom & and a more structured shape vs the Naish that had the handles & a looser wing structure...
Alex Aguera used a 3m in the first race which gave him a slow start & not enough power upwind when everyone else was on a 4m....He then switched up to the 4m for the next 2 races & got a first & a 2nd & was on the new GoFoil GL wing...