• ActionScript.SetProperty
• ActionScript.SetProperty.Float
• Math.Cast.ToSingle

• Playbacks.Editor.SelectedPlayback
• Chases.ConnectedHandle
• Playbacks.Editor.Times.ChaseFixtureOverlap

<macro id="UserMacro.SetChaseOverlap50" name="Set Chase Overlap 50%">
  <description>Set fixture overlap of connected chase to 50%.</description>
  <sequence>
    <step>ActionScript.SetProperty("Playbacks.Editor.SelectedPlayback", Chases.ConnectedHandle)</step>
    <step>ActionScript.SetProperty.Float("Playbacks.Editor.Times.ChaseFixtureOverlap", 0.5)</step>
  </sequence>
</macro>

<!-- Ricster's reply: -->
<step>ActionScript.SetProperty("Playbacks.Editor.Times.ChaseFixtureOverlap", Math.Cast.ToSingle(1))</step>
 
<!--
     Might also work. 
     Or even 
-->
 
<step>ActionScript.SetProperty.Float("Playbacks.Editor.Times.ChaseFixtureOverlap", 1)</step>
 
<!-- And as of 10.1 I think you can do -->
 
<step>ActionScript.SetProperty("Playbacks.Editor.Times.ChaseFixtureOverlap", float:1)</step>

This explains the functional steps within the sequence. For all the other XML details please refer to Formats and syntax

• ActionScript.SetProperty(“Playbacks.Editor.SelectedPlayback”, Chases.ConnectedHandle) makes the currently connected handle active in the editor
• ActionScript.SetProperty.Float(“Playbacks.Editor.Times.ChaseFixtureOverlap”, 0.5) sets the property “Playbacks.Editor.Times.ChaseFixtureOverlap” to 0.5 which is 50%

Another example was published by kimwida: http://forum.avolites.com/viewtopic.php?f=20&t=5579

1. make this macro available
2. once a chase is active and connected, fire this macro to set the chaser to 50% crossfade