What speed are you thinking of?
What about tech trades?
What rules regarding double moves, trading cities to avoid capture, spy ring co-ops for tech advances, etc, etc, etc?
Are we just going to go for whatever happens then like it or lump it?
These questions will be asked as any game progresses if a player feels ill done by so the ground rules should be, I think, set out. We shall have arguments if they are not.