Arduino + SAbertooth

[corsaveloce]

Hello

I have some doubt about the use of drivers "Sabertooth"

FOREWORD: The material I want to use is as follows:

Arduino Uno
Sabertooth
24V - 18A motors

I need to know:

A) to avoid the so-called CURRENT RETURN, do I have to necessarily connect a battery in parallel to 24V of Sabertooth?
B) If you need to connect the battery in parallel, do I have to connect one for each Sabertooth driver?
C) If you need to connect the battery in parallel, what Ah (ampere ..) must have?
D) Depending on the current absorbed by my motorgear (18A), what sabertooth do you recommend?

Syren 25
Sabertooth 2x25
Sabertooth 2x32

E) How do I set Dip switches on Sabertooth?
F) Do you know which schematic I have to use?
G) Do you tell me the link from where can i download xpid code for Sabertooth?

Thanks

[corsaveloce]

Help... please...