Last year for me… 388 across the scale at my lightest. I weighed 193 then. That means 195 allocated to kart (30mm Italkart Rapido V, 25mm stub axles, Mychron 4 with GPS, the heavier battery), fuel in the tank and H2O cooling in the rad, and driving gear (helmet, suit, gloves, shoes, Rictect 3).
I have no clue what the driver gear and fluids weigh, but personally, I include it in the weight of the kart (i.e. not the weight of the driver – me in socks, shorts and a t-shirt).