There is no way that you will ever be able to use photoreading to become ambi-dexterous. Period. You have to keep practice throwing a baseball everyday with your weak arm and just keep using the weak arm doing more physical things. It took me a long time to develop my weak arm and I still am not close to looking normal throwing a baseball or football. Just keep using your weak arm throwing things because that will be the best way to develop it. Sorry to inform you that photoreading was not going to help.
