Actually, the overall dimensions for the 5 ton M39 series, which included the M54 isn’t that much different from the 2.5 ton M34/ 35 series, about a foot in length and a few inches in height and width. Probably about the same difference as a 1/48 vs a 1/50 model.
That said I don’t know of anyone who does a dedicated M54 and that 1/64 toy looks tiny.