Hmm, Raven I?
330kg plus pilot say 80kg plus say half a tank 40kg + empty weight 655kg... 1105kg all up v max gross 1089... Oops. I guess it comes down to how fat the pilot is and how lean the fuel load.
Raven II ? 330+80+40+680=1130 v MAUW 1134 no worries can put in another gallon!