Hi flowejoe, thanks for writing - how nice to hear from you
I think most of us make bags from double-sized bits of fabric whenever the piece is big enough. If the design on the fabric has a definite direction I make the fold instead of a seam at the side instead of the bottom. You just need to offset the handles a little bit so that they are symmetrical in the middle of the bag when it is finished.
If I'm making bags out of a duvet cover I use the corners opposite the opening as they are. That saves two
seams - even better!
Why not have a look in the tips section - it's possible to make the ironing speedier by doing two layers at once, for instance, if the material is not too thick.