New install of 550-405 Terminator in a 1985 Monte Carlo. I'm using EFI timing controlled MSD 8366 distributor. I believe I need two 12V switched wires, one to switch on power to ECU and one for the MSD 8226 ext coil.

Car engine harness has a pink wire that used to power large cap HEI and a 12V switched wire that ran through oil pressure switch and powered electric choke on carb, both are 12V cranking and on.

Pretty easy for me to use old HEI wire to power ECU and choke wire (either before or after oil pressure switch) to power coil. Do you see any issues with either of those?

I've read some say it's cleaner to use a switched wire to fire a relay to power ECU. If it's preferred and I were to add a relay for this. Is it OK to use that relay to power both ECU and coil, or should I use two separate switched sources?