Hey! So I've set up 3 charts with 3 seperate controllers on a visual force page, however the information on the chart is being rendered the same for all three based on the last extension being used in the VF order.

Here's the VF build out:

<apex:tab label="Gauge Party" rendered="{!Events__c.Meeting_Type__c <> 'Argyle Conversation'}" name="GaugeParty" id="tabGauges">
<apex:pageBlock title="{!$ObjectType.Events__c.label} Gauge">
<apex:pageBlockSection showHeader="true" title="Attendee Goal" columns="2">
<apex:page standardController="Events__c" extensions="GaugeChartController">
<apex:chart name="MyChart" height="300" width="450" animate="true" data="{!data}">
<apex:axis type="Gauge" position="gauge" title="Attendee Goal" minimum="0" maximum="{!Events__c.Attendee_Number_Goal__c}" steps="5"/>
<apex:gaugeSeries dataField="size" donut="50" colorSet="#78c953,#ddd"/>
</apex:chart>
<script>
MyChart.on('beforeconfig', function(config) {
config.axes[0].margin=-10;
});
</script>
</apex:page>
</apex:pageBlockSection>
<apex:pageBlockSection showHeader="true" title="Attended" columns="2">
<apex:page standardController="Events__c" extensions="GaugeChartController2">
<apex:chart name="MyChart2" height="300" width="450" animate="true" data="{!data}">
<apex:axis type="Gauge" position="gauge" title="Attended" minimum="0" maximum="{!Events__c.Attendee_Number_Goal__c}" steps="5"/>
<apex:gaugeSeries dataField="size" donut="50" colorSet="#78c953,#ddd"/>
</apex:chart>
<script>
MyChart2.on('beforeconfig', function(config) {
config.axes[0].margin=-10;
});
</script>
</apex:page>
</apex:pageBlockSection>
<apex:pageBlockSection showHeader="true" title="Confirmed" columns="2">
<apex:page standardController="Events__c" extensions="GaugeChartController3">
<apex:chart name="MyChart3" height="300" width="450" animate="true" data="{!data}">
<apex:axis type="Gauge" position="gauge" title="Confirmed" minimum="0" maximum="{!Events__c.Attendee_Number_Goal__c}" steps="5"/>
<apex:gaugeSeries dataField="size" donut="50" colorSet="#78c953,#ddd"/>
</apex:chart>
<script>
MyChart3.on('beforeconfig', function(config) {
config.axes[0].margin=-10;
});
</script>
</apex:page>
</apex:pageBlockSection>
</apex:pageBlock>