The appears to be no simple way to set the defaults property, for the columns of a grid. from within architect.

Next to writing an override for the entire grid, is there an easy way to do it?

This is what I'd like to achieve, noting this is a sample, our grid has over 90 columns.
Code:
var fooGrid = Ext.create('Ext.grid.Panel, {
    columns: {
         items: [
            {
                 header: 'Foo',
                 dataIndex: 'foo',
                 width: 65,
                 hidden: false
             }, {
                 header: 'Bar',
                 dataIndex: 'bar'
             }
        ],
        defaults: {
             sortable: true,
             hidden: true,
             width: 100
         }
     }
});