Yes they are different sizes and I have modeled them to match. I'll get a pic of it later on tonight of the model so it will be more apparent. But in this shot you provided they are backwards and in the wrong positions due to be wilding out in a previous episode and not being put back where they belong. Since the most we ever saw this equipment used in "Elaan Of Troyius" that is the episode that I am using for the reference for the positions.
Robert Comsol wrote:
I didn't yet have a good look at the engine room's floor casing holding the dilithium crystal assembly but are the cylindrical tops on the casing both the same size?
Here is a screencap
suggesting their size is different.
Keep up this great work.