I have bought and been flying '68 235 since May with inboard and tip tanks. I was trained in a 180 with inboard tanks only. My CFI that has checked me out on the 235 insisted that land and take off on main (inboard) tanks. The issue is the POH says to exhaust the main tanks and use the tip tanks alternating every 30 min for lateral trim. It also says to fill the tip tanks and regulate the load by varying the amount in the main tanks. I have been doing the opposite. Filling only the main tanks and typically flying with empty tip tanks unless I go a long distance. This has not seemed to bother me landing in crosswind or straight and level and I don't want to condradict my CFI but am I reading 1968 info that has since been updated. How do others manage their fuel tanks? I'm confused!!