Welcome from OZ.
I like the way the hexies are put together, especially for a 'newbie', also the size of them. It seems they will be cut at 7" wide, and if you can get an acrylic template that size cutting out several layers of fabrics will be so much easier. I've just finished a quilt with 2" wide hexies, and while I enjoyed making it, at times thought I would never be done. (but I had no background fabric, and sewed together by machine, and got used to those 'set-in' points). Wouldn't hesitate to make another, but would definitely use a larger hexie for the next one.
If you choose the clamshells, do make a practice block first, to get the hang of those curves. There is plenty of advice here if you need it.