Odoo online, v12, Studio

I need to show product related attirbute values on Sales order lines.

Background

I have one product - Shirt

with 2 attributes with 2 values each.

So 

Product "Shirt"

Attribute1 "Size" Values "XL" and "S"

Attribute2 "Color" Values "Balck" and "White"

That generates one product with 4 variants

I want to add custom columns to Sales order lines so that when the product are sold their corresponding attributes are shown on Sales order lines as in a table below

Product Attribute 1 Attribute 2

Shirt         Xl                 Black

Shirt       S                   White

I have tried to add a related field, but I can make only one column, that shows the first attribute not the second

I have created a related field on Sales Order Line module with value.

product_id.attribute_value_ids.name

It shows the value on first Attribute, but how to show the value of second Attrubute in a separate field?

Can you help me to achive this customization with Odoo studio?