I'm not sure how I could sync the phone to the flashes. Right now all I have is a bunch of Vivitar 283's, I have made some brackets that will mount them together with daylight regular light bulbs as sort of modeling lights, but I wonder how accurate a rendition those would give. As for metering, I am not sure if my flash meter does reflected light readings in flash mode or just incident light readings; the former would be very useful for estimating light coverages as you have suggested. A book I am using for reference suggests adjusting the light intensities based on reflected readings but I have never used my meter as a flash meter this way, and the user's guide has long disappeared. I liked the idea of a Polaroid or d**tal camera with the same manual controls as my "real" cameras to get a more precise indication of how the final shots would look - but you are probably right, atleast I think you suggest implicitly, that with experience perhaps the need to do this goes away.