Power feed for megasquirt

[ChaosAD]

Im in the process of wiring a 'Megasquirt' ecu into my 4age powered ae82.
I have wired in everything except the power and ground wires.

As far as I know there are three main power wires going to the factory ecu which are on when the key is on. +b, +b1 & bf.
+b and +b1 are connected together and come from the efi main relay via the 'car loom'. bf comes from the feed for the coil and injectors which I think comes straight from the ignition switch.

What would be the best to feed the new ecu with?

[Malcolm]

+b and +b1 are the ones that power the stock ecu, I would tend to use them.