As I'm pretty familiar with the g1 toy i built this from memory and found it pretty easy with just a few snags to fix along the way although the chest was a bit hard.
like the animated figure this has more articulation in the arms and legs than the original although the alt mode is a bit rigid apart from the head neck and legs and is probarbly more comparable to classics Grimlock.
With the animal tfs size is not really an issue as there is no need for a mini fig to fit in so you can make them really big (I'll post my Spapdragon and Transquito then you'll see) which is always fun plus it allows for greater detail and better articulation
anyway i hope you like it cos this is one of my favourite lego kitbashes. Comments and critisism are very welcome as I'm always looking to improve.