That was to a question regarding beam size based on charge time, not per form.I want to attempt to help you, but don't be ghey if I'm wrong.
I remember someone from the dev team saying that charging a beam (like a Kamehameha) doesn't affect explosion size which makes me believe that there will be no difference. Charging only affects damage, speed and turn rate.
No i dont mean different attacks, i mean different versions of the same attacks.like the spirit bomb and final flash
Yes and no.To simplify what Grega said, the beam becomes stronger (and potentially bigger) each time you transform into a higher form.