In terms of customizing, there are a couple of good approaches:
1) Follow the first few steps verbatim, usually through late morning, then improvise after that.
2) Follow the general advice, rather than the exact steps.
In the first method, you'd use the touring plan's first five or six steps exactly as written, then go with the flow afterwards. The rationale for this is that the first few steps usually include the most important attractions for a given plan (e.g., Dumbo, Space Mountain, Test Track, Rock 'n' Roller Coaster). These things usually ease up just before lunchtime.
For the second method, you'd follow the general spirit of the plans rather than the individual steps. So if the touring plan has Fantasyland attractions first, you'd still visit there first, but not necessarily each attraction in the order shown. If the second land visited is Frontierland, you'd still visit Frontierland second, but not necessarily following the exact steps shown.
Of all the general purpose advice around customizing the plans, I think these two generally meet with the most success.
If this is a topic of interest, I can write up something more detailed for the website. Let me know if that'd be useful.
Sincerely,
Len Testa