All Alloy Cup progress

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Thread tension.
Use the lightest you can achieve without the thread losing contact with the face of the cloth, try to not 'gather' the fabric. 
The top and bottom tensions should be equal so threads cross in the 'middle' between the plies, easier to see in multiple plies of thick material.   Looping at the bottom more top tension, looping at the top more bottom tension. Bobbin tension is often not easy to adjust but it does set the range of thread tension available to you.  Useful stitch length is 6 per inch. As others have said practice on scrap fabric of a similar weight but do mark out with final fabric, I NEVER make patterns and transfer to final fabric. My business was canopies with a strong interest in vintage work. Others I appreciate may have a different approach, crack on