I was inspired by Jane Sarre’s blog entry about aprons to share my own experience. Look at her examples too – they may suit you better.
This is my version of a throwing apron that Carina Ciscato brought back from Brazil – you can just see the overlap in the pictures on her website.
I’ve found a similar version online, and also on etsy, but both from the USA. I made mine, it’s not too difficult, the main thing is to make it long enough – measure waist to ankle for the two big oblongs, as the apron rides up while throwing. It’s better made in a tough washable material like cotton – too thin and the clay comes through, too thick and it takes a long time to dry when washed.
I suspect with a closely woven material you could get away with no hems. If you use tape or webbing for the straps, you could get away with only needing to sew one seam, along the overlap, and catching in the bib, then attach the straps. I often use safety pins for a while to do this, to get a comfortable fit, before sewing them down.