I like having a timer idea. It creates a bit of excitement in determining your purchases and movements as you are “on the clock”.
I also think most of the first 1-2 rounds are or at least should be pretty much pre-determined. It helps if in the early going people play the same nation a few times in a row so that you can minimize the learning curve of implementing that nation’s strategy.
1. Germany
2. Soviet Union
3. Japan
4. US/China/UK
5. Anzac/Italy
6. France
That shortens the turn order a bit and really doesn’t conflict too much. Just try to be sure someone isn’t controlling China/US/UK all at the same time. Better to have 2-3 people managing those 3 countries than just 1.
The biggest key I can give you is to eliminate table talk during the round. No talking except between each round. Give a 10 minute window between rounds for bathroom, refreshments, smokes, and strategy. Each side leaves the board for 5 minutes so the other can talk shop over the board.
It also helps to have a pen and paper and write down your moves and whats coming from where beforehand. The greatest plans never turn out exactly right, but at worst you have a record of what you missed, what worked and notes around what happened. At best you have a speedy plan to move through the game. In example, its really frustrating waiting for Italy to decide what to do with its fleet on Round 1, so the strategy should be pre-planned with contingencies for what the UK decides to do instead of spending 15 minutes debating, 10 minutes deciding and less than 5 minutes moving / rolling dice.