I have no idea what the MS3D scale is for Blockland, and can't find it anywhere, though you could model it in MS3D and then load it in Blender and scale it there (one 1x1f in Blender is 1*1*0.4 Blender Units).
Make a cube and test how big it is compared to a brick
It would take hours and hours of loading blockland, Quitting, Rebooting blockland, Resize, Reboot again.. There has to be a better method.
I hope it wouldn't take hours as long as you make educated guesses on how to adjust the size.
Can I also ask how do I make bricks... ? I mean. I import the dts file, Fine. What then?