Not all hemp thread is equal. Some of it is very rough amd lumpy.
I use the Carriage Brand hemp thread from Tandy and like it a lot.
https://tandyleather.com/products/c...78787&pr_ref_pid=4503288217731&pr_seq=uniformIt comes in two thickness options and several colors
https://tandyleather.com/products/carriage-hand-sewing-thread-085-mm-35-yards
I have a side of Kodiac oil finished cow leather. It is incredibly flexible for such thick leather, but, also very heavy and the combined actual weight and flexibility can make it hard to work with.
Be sure to check out some of the saddle stitch videos that
@Artificer has linked to in the past.
If you don't have a pricking iron or overstitch wheel to lay out your stitch spacing, you can also use a set of dividers, or some other spacing device. I used a wooden coffee stirring stick to get my spacing between stitches when I sewed the tape binding around the edge of my hat...
View attachment 201596
You can kind of see the stick under the hat. Each stitch is the width of the stick, there is a line drawn across the stick that when held even with the edge of the hat shows me how far from that edge the line of stitch goes (royal pain in the ___, I hate sewing fabric)
Go slow. Keep your awl sharp, really, really sharp.
I have full topics on each of these projects that might include more helpful pictures.