>>6206138>>6206195Dinobot was a head taller than Primal at most.
In most shots, he's in the back, which puts his feet higher than the others, so he appears taller, but in reality, Primal comes up to his chin.
Which means Dinobot should still be smaller than Soundwave (certainly less bulky)
Megatron would be about the size of the original masterpiece Prime, considering the first iteration of BW Megs was also the shortest. He was maybe two 1/2 heads taller than Tarantulas (who was roughly a head shorter than Primal)
For something UM scale it would need to be one of the biggers, Tigerhawk, TM2 Megs.
Oddly, I think for a proper scaled Optimal Optimus, he'd be the biggest masterpiece to date, so I doubt we'll ever get him.
Honestly I doubt we'll ever get anything past season 1.