The reason the 5 SPEED does NOT have the grove
It compromised the unique and very important (THIN profile) finger thickness and increased the vertical forces into the fingers.
that it limited the head postions to x2 there are x4 on the H&F
It is not nessesary anyway as the amount of force need to fold modelling etch brass is very low, Get or make a good Stiff blade to work with, thin razors are poor as they flex
IF you need to (like some train Kits) bend thicker stock, then position the part to the outside edge, hold the tool in your hands like a sandwich (part facing away) and use a table top to press/roll against, simple, quick and a better fold as well. (Two hands/solid base to roll against=better results)
I was, But am not now connect with the H&F