The size of the sculptie is not dependent on the size of the sculpt-map. The sculptie size can be modified inworld by adjusting x,y,z in the prim editor.
Please be aware: The standard viewer allows only sculpties with 1024 faces and sculptmaps which contain 32*32 faces.
depending on what sculpt type you have, this means in count of vertices:
33*33 vertices for planes
33*32 vertices for cylinder and sphere
32*32 vertices for torus
the difference comes from the different stitching types:
plane: no stitching at all
cylinder: stiched at one side
sphere: stitched at one side, the poles shifted together to 1 point
torus: stitched at both sides
Domino's sculpt maps always use 64*64 pixels. I am not sure, how exactly this technically maps to the vertex counts i mentioned above for the different stitching types. But still, only the amount of vertices as mentioned above is actually derived from the sculptmaps. In simple words: whatever sculptmap-size you supply, the viewer always shrinks down to the vertex count i mentioned above depending on the stitching type.
All what i have said so far is valid for the standard viewer. The RC-viewer can do other face counts. Now sculpt maps do not need to be square, but can be rectangular. All supported UV face counts are (as far as i know) supported by Domino's RC-scripts. But as far as i know, even the RC-viewer does not allow for more than 1024 faces in total.
If you want to keep compatible with the standard viewer, only use sculpties with 1024 faces. Hence Domino's scripts and 64*64 sculptmap size is most probably what you want
