If possible, keeping the injector BPW close to the original value is best. I would consider using an injector with a higher flow rate to keep the BPW near the original value. Injector offsets and injector parameters are very important. I would closely compare the higher flow injector parameter with the original injector parameters.

For example, you might be able to use 305 injectors at 35psi to keep the BPW close to the original value. I STRONGLY recommend flow testing 305 injectors at 25, 30, 35, & 40 PSI to see which pressure is best for keeping the BPW near the original value.

I don't know of a formula that would convert BPWC to Milliseconds.

dave w