Newbie question. Second try

Hi, One week ago I posted a question, but something have not posted
any reply.
If the question is dumb or not interesting I apology.

I have 3 drivers based in L297 L298 combo.
The first thing different an other combos is the next phrase in the
operation manual "The new SD1V1.2 incorporates half step shaping for
95% torque of full step mode"

I have got 4 surplus motors with the next technical data:
150 oz-in Nominal, 4.5V, 1.4A, 2º/step, 6 Wire, Nema 34, Single
Shaft.

I am planning wiring this motors in half winding based in earlier
recommendations in this group.

In Mariss Power Supply tecnical white Paper, the recommendation is "
THE Driver will always draw less then 2/3 of the motors rated current
when is half winding "

With the above parameters what is the suitable amperage in order to
configure the chopping subsystem (PWM) ?
1.4 Amp or (1.4*2)/3 = 0.93333 .
If the amperage is < 1.4A am I lossing torque ?
What´s the matter if I set Vref in order to get 1.4 amp ? Could I
fried the motors ?
What is the meaning of half step shaping for 95% torque of full step
mode.

Insulation and Grounding

I am planning wiring the motors with 18 awg shield 4 wires. The
question is... The aluminion foil of the shield must be connected
only in one end
What end ?
The motor case end or the drivers and Power Supply case, exactly in
the same point where is attached the power ground cord.

Thanks in Advance