Re: masks
I have been sewing the twist tie wire in the lining seam allowance zigzaging over the twist tie making sure the width is wider than the twist tie and being careful not to hit the wire with my needle. It's working well for me.
Also before sewing the front and lining together I fold up the sides 1/4" and press. Unfold the fold when sewing the upper and lower seams. When it comes time to fold in the ends it works so much quicker.