I remember that being the case in older versions (been a while since I played) but now I can only set the size and explosion radius of the blasts from the options and config file without having a dynamic option (even after removing all the limits in the config)
I also noticed that the only way to increase them is ONLY through the Oozaru transformation even when other transformations are much stronger. This also doesn’t seem to correlate with your stats or charge percentage, as 10% powered Oozaru has bigger blasts than 100% powered SSJ3 with maximum charge.