This question is slightly related to \a previous one I asked, except I believe I found a way to do what I want (which answers the previous question). I am trying to combine multiple models into the same view, and according to the docs, this forum, stackoverflow and random websites, what I want is to inherit the main view and use an xpath to insert my fields.

My main view is this

<record model="ir.ui.view" id="erpwarehouse.mainviewrec">
 <field name="name">erpwarehouse.form</field>
 <field name="model">erpwarehouse.erpwarehouse</field>
 <field name="arch" type="xml">
  <form string="Test">
   <sheet>
    <notebook colspan="6">
     <page string="ERPWarehouse" name="erpwarehouse" autofocus="autofocus">
      <label for="estimate_id">estimate_id</label> <field name="estimate_id"/> 
      <label for="worder_id">worder_id</label> <field name="worder_id"/> 
      <label for="receiving_id">receiving_id</label> <field name="receiving_id"/> 
      <label for="production_id">production_id</label> <field name="production_id"/> 
      <label for="billing_id">billing_id</label> <field name="billing_id"/>
     </page> 
    </notebook> 
   </sheet>
  </form>
 </field>
</record>

I have tried the following possible solutions to try to get my other views to show up as extra pages in the notebook defined above (one for each of the fields) to no avail.

<record model="ir.ui.view" id="erpwarehouse.estimateView">
 <field name="name">erpwarehouse.estimateform</field>
 <field name="model">erpwarehouse.estimate</field>
 <field name="inherit_id" ref="erpwarehouse.mainviewrec"/>
 <field name="arch" type="xml">
  <xpath expr="//notebook/page[@name='erpwarehouse']" position="before">
   <page string="Estimate">
    <field name="project_scope"/>
   </page>
  </xpath>
 </field>
</record>

<record model="ir.ui.view" id="erpwarehouse.estimateView">
 <field name="name">erpwarehouse.estimateform</field>
 <field name="model">erpwarehouse.estimate</field>
 <field name="inherit_id" ref="erpwarehouse.mainviewrec"/>
 <field name="arch" type="xml">
  <notebook position="inside">
   <page string="Estimate">
    <field name="project_scope"/>
   </page>
  </notebook>
 </field>
</record>

<record model="ir.ui.view" id="erpwarehouse.estimateView">
 <field name="name">erpwarehouse.estimateform</field>
 <field name="model">erpwarehouse.estimate</field>
 <field name="inherit_id" ref="erpwarehouse.mainviewrec"/>
 <field name="arch" type="xml">
  <xpath expr="//page[0]" position="before">
   <page string="Estimate">
    <field name="project_scope"/>
   </page>
  </xpath>
 </field>
</record>

I have also changed the id and name of the record to be erpwarehouse.mainviewrec_inherit, but that did not appear to do anything. Am I missing something? Any help would be greatly appreciated!