From what little looking I did, it seems Suter's Choice bullets were made by an older fellow in IL. A few years ago, Graf's and some other retailers were selling his bullets.
More recently, it seems he may have retired.
As for hardness?
My rule of thumbnail is:
If I can scratch them, they are soft.
If I can't scratch them, they are hard.
If they shatter when bent with a hammer, they are very hard Linitype.
So, try scratching them with your thumb-nail.
If you can scratch them, they are soft enough for standard pressure .38 Spl loads.
If you can't scratch them, they are more like harder for Magnum velocity and may possible cause leading at low pressure.
rc