Just use these rules.
1. You have to have your purchase ready, by the start of your turn. (Yes that can mean you organize several purchase options) If you don’t have one ready, you don’t get to purchase.
2. You have 5 minutes (Use an hourglass or stop watch) to place all your combat attacks, Monitored by opposing team.
Roll Dice, then after all dice are rolled…
3. You have 5 minutes + whatever time you didn’t swallow up from your combat moves to do all your NCM.
You SHOULD make the time alotments dependant on per country (China doesn’t take 5 minutes to do the whole turn, but Germany or U.K. can take time…)
Also, allowing players to play simultaneously (Germany+Japan with Russian eastern forces moving, UK + ANZAC, ETC) Significantly reduces time in game.
You could also reduce times to very low, but keep a consecutive clock, IE you save timed last turn, so have it this turn.
OR allow the player for 1 IPC to buy 2 minutes of time,
OR allow each side a certain amount of TIME OUT’s for team meetings.
OR just play the game with experienced players and tell everyone to move quickly.
BEST Pick the teams days BEFORE the game, so they can talk up a good strategy, and know their respective roles.