Hello! I'm based in Europe so have done all the layout and design for A4 because that's all I can print on my printer.
I probably won't be doing a US letter format version as I don't have any publishing software and have to do everything via photoshop (which makes everything take longer).
I know from folks in the US that it is possible to print my game documents on US Letter paper by adjusting the print settings (i.e. fit to page).
I'm sorry for any inconvenience caused.