Why 30 or 40? Why not 35 minute halves for JV? I think 40 is too long and the level of play would suffer (more than it already does) towards the end of the half and definitely the game because of the fitness level of the young players.
I like OT but i see no need for PKs in regular season games. A game that finishes regulation tied should go to two 5 minuite golden goal periods. After that, end the game in a tie.
I think at the varsity level, play two 10 minute golden goal periods then end in a tie. For that matter, in the playoffs, continue to play 10 minute golden goal periods until someone wins. While as a coach, I do not like deciding games on PKs, as a GK i loved it b/c iwas the one in the spotlight.