Few questions about Sniper wiring

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I’m installing a Sniper efi on my Chevelle with a trunk mounted battery and AAW classic update kit. BBC with HEI. I have a few questions about the wiring,
1. Main power wire, does it need to go all the way back to the trunk mounted battery or can I pull power from the AAW fuse panel or from a distribution block that I have near the starter which is connected directly to the battery? Can I ground to a clean chassis ground or does it have to go back to the battery?
2. I already have a pre-run wire from the AAW for an electric fuel pump. Can I use this wire or do I need to use the fuel pump wire that comes in the Sniper harness?
3. The yellow wire for rpm input, can I plug that in to the HEI if I’m already using the tach location on the HEI for a DD tach? Basically, can I piggy back the tach output and the efi rpm input from the same location on the HEI?
4. Switched ignition wire, what’s the best location for this? Up to the ignition switch, or can this be pulled from the distributor? Other location?
Thanks for any help!