Look a tidy job,
The only issue you will have there is the voltage correction tables in the ecu firmware, there are correction tables in the firmware so the ecu looks at the battery voltage and corrects the injector time accordingly, If the voltage drops so the injectors slow down the ecu will counter this by opening the injectors a little longer to counteract them slowing in operation.
This is the same scale we change to make big changes in injector sizing.

Its vital for this reason that the ECU and injectors are on the same power relay so the scaling works correctly, The way you have it wired there it would be possible for the ecu voltage to tail off, so open the injectors longer, but the injector voltage has not actually changed and slowed them down and the AFR will be changing wildly.

This is the issue when people make looms who dont know the ecu well enough to know what they need to work. We see lots of similar looms built here that are ok but dont work very well because of small issues like this, and the ecu being grounded at the battery is another we see quite often.