I would say one creator's note is enough. In future chapters, it's up to the readers to read the creator's notes, anyways.
For some advice on the small text, I also had a small text problem in the beginning. After that I adjusted the layout of future pages so that they would fit more text, also trying to make the dialogue more concise (concise dialogue is usually better anyways).
Since your pages are in print format, I've found that 18-30 point size is more well suited than the standard point size for scrolling comics (which are about 12-16 point font). The width of a print size page will reduce the proportion size of the text on the screen, as opposed to scrolling comics which are typically narrow, so smaller point font would still look proportionately big when saved as an image. For current pages that had the problem I just left it as is unless if sometime in the future I had time to fix it.