Grade 3's sheer amount of energy was stated to be greater than Cell's
SSJ2 had a much greater reaction to the sheer amount of energy by the Z-Fighters and even by Cell... Cell's only comment on Grade 3 was that it gave tremendous strength but no speed.
Also... I dont think Frieza would let Vegeta transform.
Great Ape is already something he's seen and clearly hates. He is shooting Vegeta as soon as he forms the Power Ball (Assuming this fight is on Namek... Namek has no moon)
Pretty sure Frieza would just move faster than Vegeta could react...
Vegeta gave up against FF Frieza after he saw the difference in their power and speed.
Great Ape Vegeta doesn't seem to get any faster than he normally is... so Frieza is still faster.
Frieza cuts off Vegeta's tail and then...
I watched all of SDBH...
It was... ok? Cant call it a "Filler Show" while you go figure out what else to watch since its just an Ad for a Now Shut Down Arcade Game...
but... it has its moments... (Except the Majin Ozotto shit looks horrendous)