A question of scale

Hey guys, I'm still very much a noob here and was just looking for a little bit of information. I'm looking to collect masterpieces and 3rd parties of a similar scale, but was just wondering if all the Hasbro/Takara are scaled appropriately compared to one another?
I already have Prime and I have X-Transbots Apollyon on order and he looks to size up perfectly against him, I also have Maketoys Giant (Devastator) which obviously isn't to scale, but unless they make a 3 foot tall one I can live with that!
I may be going mad but I seem to remember seeing Soundwave in different sizes, possibly the same with Grimlock. Are there different/multiple Starscreams, Soundwaves and Grimlocks? I have seen there was a Coronation Starscream and a King Grimlock, were they scaled differently to the regular releases? Can anyone drop a knowledge bomb on me please? Pics would be appreciated too
I already have Prime and I have X-Transbots Apollyon on order and he looks to size up perfectly against him, I also have Maketoys Giant (Devastator) which obviously isn't to scale, but unless they make a 3 foot tall one I can live with that!
I may be going mad but I seem to remember seeing Soundwave in different sizes, possibly the same with Grimlock. Are there different/multiple Starscreams, Soundwaves and Grimlocks? I have seen there was a Coronation Starscream and a King Grimlock, were they scaled differently to the regular releases? Can anyone drop a knowledge bomb on me please? Pics would be appreciated too
