7.5" from the tip of my middle finger to the first fold on my wrist. Palm = 4.25"; index finger = 3.25".
Starting from the tip of fingers:
Thumb, first joint; not a total pinch grip, but bracing against the first joint.
Index finger, second joint like a pinch grip
The small polymer HTS is 3/4" thick while the regular HTS is 1". The small HTS is about .2" narrower in between the index finger and thumb cut out. This, combined with the 1/4" thinner slingshot allows me to pull stronger bands,
I am really happy with both my HTS and small polymer HTS. I have a medium Seal Sniper in poly, which felt even larger than the HTS. After receiving my small HTS - I had the courage to modify the Seal Sniper to match the Index finger - thumb width of the small HTS. The Seal Sniper is now much more comfortable for me.
I hope this helps.