Back in 2003 with HOI1, I used to have a regular group of fellow college students who could literally waste an entire weekend playing.
There were 5 of us and we rarely could finish the game properly for various reasons.
Foremost is that if you start in the GC it takes upwards of 20 hours to even finish and im being extremely generous. Combine that with the fact that generally the game ended the moment Germany or the Soviets got the upperhand. We never actually took a game through to its actual conclusion. Usually the game ended with either the Soviet player or the German player throwing in the towel once defeat was imminent.
The biggest draw back to HOI multiplayer is that you REALLY need to have all sides represented.
If you cannot get all sides represented and by this I mean Germany with Japan and Italy, don't stick someone into the game as Germany. Instead do a comintern/allies game. To provide a challenge, from the axis prior to the actual soviet/allied showdown have all your players go into the difficulty text file, and give the axis a large manpower and IC boost, perhaps research as well. This will ensure that by the time they invade the USSR they have a mass of units.
Frankly, having played the Germans its really no fun when you have a good soviet and a good USA player. You're screwed no matter what happens. Not only that, but you're also out of the game extremely early. We always found it more enjoyable to have our shooting war start immediatly after the fall of Germany, with europe divided amongst allies and the USSR. This way everyone is in the game till the end, and nobody felt excluded while we spent 2 more days finishing the game ;p
In the end, you can be pretty flexible in how you want to play. Just understand that it is a HUGE time investment. Regardless of you playing a few hours a couple times a week, or devoting a case of doctor pepper and a weekend to the session. Either way plan for 20+ hours at the bare minimum.
Last a word of caution. The game is what you make it in multiplayer. Due to the fact it is a massive time investment, it can be extremely rewarding and fun, or it can be a huge dissapointment for one or everyone involved. Games that end after Germany or the Soviets quit in disgust of losing an important chunk of their military are extremely dissapointing for everyone involved. Make sure the people you have playing these two vital countries if you choose to go this route are stubborn and dependable. You do not want 16 hours down the drain because your Soviet player throws in the towel when he loses 20 armored divisions. These people literally need to play to the brutal end.
