Formatting the y-axis of a chart

Originally Posted by Andy Pope

Simplest way is to build the axis labelling yourself with a dummy data series
http://peltiertech.com/Excel/Charts/ArbitraryAxis.html

Is the principle involved here : 'to use dummy data to get the desired formatting of the y-axis but have the dummy points invisible as they will lie on the Y-axis, and then to plot a 'second' set of data (the REAL data) ? I suspect that second set of points will have 'default' colour and shape - can THEY be customised - if so how ?