@WharfRat - I totally agree. Some of us are very visual, and having a graph visualization is very helpful.
I use the UK EasyTide as my reference when working in the Antarctic, and it works most times.
- I think the Amazon River Basin will provide unique challenges. There is an annual variation that can be bigger than 10m at Manaus, plus daily tidal variation that can be noticed all the way to Óbidos (800 nm from ocean). Then the rivers on the North bank have their flood in Spring, while rivers from South Bank have theirs in Fall. There are tide gauges in all main cities.