I took this image into Adobe Illustrator to add the color dots that represent the “studs” of the bloks. Then I put it in Photoshop to fix the box’s perspective.

Here’s the original: 

Here is the fixed perspective with color studs:

Now for the “math.” Each dot represents a “stud” on the top of the bloks. Each fifth dot is a different color to make it easier to count. The height is calculated by plate size, not studs. (I didn’t show the control tower dots near the top right in this graphic)

Red+Yellow length of studs I counted at 85 approximately.
Blue+Green length of studs I counted at 21 approximately.
Orange+Purple height of plates I counted at 48 approximately.

I measured the length of studs. Each 2 stud blok measures 1.5cm. Each plate is 3mm high (not including the stud at the top)

So that means each distance is:
Length 85 studs=67cm=26.375 inches (inches are rounded up)
Width 21 studs=16.5cm=6.5 inches (inches are rounded up)
Height 48 plates high=16cm=6.3 inches (inches are rounded up)

Folks, this is a BIG set!. Also, bare in mind we can’t see all the bloks near the aft end of the set, so it could be even longer.

So again to put it in perspective:
Over 2 feet long by more than a half foot wide, by half foot tall(again approximate)