
The following is a study of the Marine Corps regulations concerning ribbons. Most of the regulations are straight forward, but there are some exceptions that can be left up to interpretation.
Choice of spacing.
Parallel rows of ribbon bars will either be spaced 1/8 inch apart or placed together without spacing at the individuals option.
Wear your ribbon rack three or four ribbons wide.
Ribbon bars are normally worn in rows of three; however, rows of four may be worn when displaying a large number of awards.
Staggered right configuration is allowed.
Two-ribbon rows may be worn when ribbon bars are worn in successively decreasing rows. Female Marines may also wear two-ribbon rows when a three-ribbon row would not lay flat or would extend too close to the armhole seam.
You may choose to center or stagger the ribbons to the right. If you choose standard ribbons you will not have a choice of four wide due to manufacturing limitations. If thin ribbons are selected you can choose from any configuration you like. Spacing is also available for all the configurations below.

Silver claims higher precedence over bronze and gold.
Silver star(s) worn with a bronze or gold star(s) will be worn as...the first bronze or gold star is placed to the wearer's left of the silver star(s) with additional stars alternating to the right of the silver star and so on.
The V device has precedence over the other devices
Gold, bronze, or silver stars, or oak leaf clusters worn to indicate subsequent awards will be evenly spaced in a horizontal line on the ribbon bar with the "V" at the approximate center and the stars arranged symmetrically in relation to the "V"; the first star to the wearer's right, the second to the left, and so on.
Regulations for the Navy E ribbon, otherwise known as the battle E ribbon.
Individuals awarded the Navy "E" Ribbon will wear a silver block letter "E," 1/8-inch high, centered on the ribbon. Subsequent awards are indicated by an additional silver "E" attachment for each award. When more than one "E" attachment is worn, they are placed in a horizontal line evenly spaced, centered on the ribbon. For four or more awards, only one 1/8-inch silver-wreathed "E" attachment centered on the ribbon is worn.
Below is a picture of device configurations on ribbons taken from the regulations.

As for the rack builder we interpret the regulations concerning ribbons as follows:
Note:
These interpretations are based on physical spacing on the ribbon and the Marine Corps Regulations.