Merge 2 tables with same column name and duplicated products

Firstly, I would start with a base table. I would append query as new, select the two tables and then remove duplicates from the Product column. This would ensure all the products from both tables are there but no duplicate products. 

MY next challenge would be addressing the blank attributes. (i.e. Color, Size, Price and Range.)

On appended table, I would merge query with table1 (left outer) on product and then expand Color as Color1, Size as Size1 and so on. 

Do a conditional column called color2, if Color is blank then Color1 else Color. 

another column size2, if Size is blank then Size1 else size 

and so on

This ensures all the attributes from table 1 are included in the columns color2, size2 ad so on. Now I want to bring in attributes from Table 2

I would merge query with table 2 (left outer) on product and then expand Color as Color3, Size as Size3 and so on. 

Do a conditional column called color4, if Color2 is blank then Color3 else Color2. 

another column size4, if Size2 is blank then Size3 else size2 

and so on

After doing this Color4, Size4 and so on should have attributes from both table 1 and 2 while the appended table will have all unique products from both tables.

Rename Color4, Size4... to Color, Size and so on.