Austin - Using the Open Office route, the question of producing a consistent final size for the chord diagrams shouldn't be too difficult.
Starting in the Draw bit of the package and using the same basic grid for the diagrams, you should be importing a standard size of diagram into the word processor.
As you import into the word processor you get a graphic element which is quite big relative to the page, but when you find the resizing controls, they allow you to a pretty fine control over the reduction in size. The two things to remember are firstly that if you get it wrong, there is an "Undo" function in the Edit bit of the menu. Secondly, in the resize box for the imported graphic, you need to check the box to keep "aspect ratio" when you alter one dimension to keep the other in proportion. If you are using a grid with strings horizontal, it will be 6 strings deep. The chord diagram might be 4 frets long or 6 frets, so is a variable . The 6 strings for a guitar is fixed. Use the 6 string "height" as the dimension you alter, and the variable width of the diagram kept in proportion to the number you change ought to give you a chord diagram size the same each document.
Quack!
GtD.