This is all old world guidelines that people came up with to get around the limitations of pen and paper. The new world guideline for those who use electronic notebooks is to use one that enforces non-deletion. Get a good witness . The witness really should understand it, as you can read about interference cases when the witnesses, like lab assistant were dismissed by the judge because they were really too junior to understand what they were reading and signing. The witness should sign it as soon after you complete each record as possible.
Some people get confused and think a notary is a witness.
Update your record often . There's no rule, but basically you're building your own case and you have the luxury of doing it in advance. The more entries you have in a span of time, the less likely any counter-party could claim abandonment and the more details you will be able to substantiate. Start now , even if the project is already underway. Although you cannot back date anything, you are absolutely permitted to write a summary of your idea development to date, and then sign, date and have it witnessed as of the current date.