The rounds are about palm-sized and are nice, solid slices of wood. I’ve had the best luck with simpler designs on these (ex: snowflakes, silhouettes and stuff that doesn’t have as much shading) but that could just be me. You will definitely want to give them a good sanding before you start to make things easier.
For the squares you’d need a little craft drill to put a hole in for the ribbon, but I like the extra space and evenness of them. Here’s an example of some of mine (please pardon the clutter): Square ornaments