Here are three more seam treatments
I've done for my hussif.
The top one shows how a very simple
seam can be created by just using
ordinary buttons held down by a bead.
The middle is just two rows of cretan stitch
with sequins held down by beads.
The bottom is done using
It's not absolutely necessary to use waste canvas,
but if you want your stitching to be even
it is an invaluable tool.