Resizing or scaling the chart does not affect the Spectroscan unless the patch size gets either too small to measure (the absolute minimum size you want to read is 5mm) or too large to fit on the table. For MeasureTool usage, you align the Spectrolino head to three of the four corners. MeasureTool then calculates where each patch is. If you use Argyll and its hexagonal patch layout, the tolerances are tighter. I hesitate to go below 6mm on them.
The easiest chart building utility I have found is
X-Rite's ColorLab. Load a CGATS file and export a tiff image. Sizing the image is easy - multiply the number of rows x desired ppi = vertical pixels, repeat for columns. Open the tiff in Photoshop and set the resolution to 360 ppi (do not resample, just a resolution change) and you are done.
MeasureTool output files can be loaded into i1Profiler. Just drag-and-drop onto the measurement panel.
For connecting a Spectroscan to your computer, the Keyspan adapter Terry recommends is a tried and true option. We have used other USB to Serial adapters with mixed results. Keyspan works. If you use Windows a even better alternative is an add-in serial board. We have used ones from Startech that include a "UART" (an on-board serial controller), both PCI cards on older computers and PCI Express on our current systems. They give bulletproof connectivity, cut the MeasureTool's CPU-hogging down to useable levels, and do not show the occasional data error that even a Keyspan adapter has. As far as I know, however, there are only Windows drivers available for these cards.