Custom Goal / Target on Chart

Hi,

Struggling here I need to try and create targets / goals based on monthly targets for each Account on a count of Opportunity Products targeting the Model (Segment) attribute of which there are 12. 

Account A has targets of Products grouped by Model (Segment) type

Products (Model 0-40) target 3 units

Products (Model 40-60) target 2 units

…………...

I created the relationships below and have no issue showing a chart of all related Opportunity Products grouped by model on the Account form.

I also created the custom goals entity as shown below however can't see clearly how I can get this as a line on my existing chart mimicking the OOB Goals.

I have attempted creating some OOB rollup queries without success.

I can get the values into a fetchxml query but at a loss, although thinking about count distinct.

Here is the fetch I can get where I can get Segment and related Goal / Target

The FetchXML

<fetch>
  <entity name="opportunityproduct" >
    <attribute name="new_accountid" />
    <attribute name="productid" />
    <attribute name="extendedamount" />
    <attribute name="baseamount" />
    <link-entity name="new_goal" from="new_account" to="new_accountid" link-type="inner" alias="Goal" >
      <attribute name="new_model" />
      <attribute name="new_goal" />
      <attribute name="new_account" />
    </link-entity>
    <link-entity name="account" from="accountid" to="new_accountid" alias="accountOp" />
  </entity>
</fetch>

Any ideas?