I'm not sure if there would be a better place to post this but I have a few comments regarding the character sheets.
1) Why have the characteristic blocks twice. It seems completely unnecessary.
2) To allow for easier copying / printing as well as visual clarity, use a predominantly white background. Borders are fine and even appreciated, but the grey wash uses a lot of toner and makes pencil difficult to see.
3) I might suggest the creation of another sheet to record the rules and information for player-made regiments. It would have lines for the major regimental options (homeworld, commander, type, training, special equipment, kit changes). Also, include areas to record backstory / fluff; perhaps a couple lines follow the options mentioned above where the party or GM can elaborate on that specific feature.
In all I wanted to say that Only War crystalizes the concept that drew me into playing Imperial Guard on the tabletop. It provides the first person perspective on the 40k universe that people can empathize with. It wouldn't be the same if it was a space marine's perspective because of the insulation provided by the armor / superhuman qualities. Great work. I look forward to playing and I wish I could move to Minnesota to work with you all.