- Blind increases - Anything more than a 50% increase between levels usually feels like it's forcing the action. Likewise having blinds increase slowly in some stages of the game and doubling in other stages keeps the game from having a smooth flow. Further it may unfairly reward those who catch cards when the blinds are increasing quickly.
Level times - Levels should last at least one orbit. That means 12 - 15 minute levels for a non-turbo format with 10 player tables. Reasonable and consistent blind increases aren't enough if the BB has jumped two or more levels every time it hits a given player.
Starting stack - The size of the starting stack should be such that the level where the BB is 1/10th of the starting stack occurs at about the halfway point of the game. Things like rebuys, add-ons and antes will need to be factored in as they affect the point in the game where blinds begin to force the action. A game will typically end at the level where total chips in play divided by two is ten times the BB. In other words if we are down to heads up and the two players have equal stacks, each of them will have 10 BBs. Use this to determine your last level of blind increases.
NOTE: The above recommendations will prevent the need to use the dreaded "Double blinds/antes after last defined level" option. You choose the blinds and starting stack for the first level, and the number of players along with starting stack determines the blinds for the last level. So just fill in the levels between the first and the last with a reasonable, consistent rate of blind increase, and you've got all the levels your format will need.
Players per table - I prefer 6 to 8 per table simply because the rate of hands per hour is so slow in DD with full tables. Making levels last at least one orbit for a 10 player table is obviously going to require longer level times.
Total players - A game should start with an appropriate number of players for the players per table setting or vice versa. Why have a format with 10 player tables and then start with 12 players? The game will start with two short handed tables and then merge to a full table. That often creates an advantage for anyone who catches cards early while the tables are short handed, and makes the game feel rushed after the tables consolidate because players see fewer hands per level. Instead I would recommend using 8 or 7 players per table if you are going to start with 12, or just start with 10 and a full table. Also, try to start with a number of players so that all tables will be even (ie. an even number for two tables or a multiple of 3 for three tables).
Small blind - There seems to be a trend in DD formats of making the SB more than half the BB. Whether it's to justify playing more hands from the SB or create more action, it's unnecessary (there will still be plenty of action) and prices players in to a bad habit.
