Thank you for the replies, guys.
Thoughts from anybody-else?
I am asking as I would prefer to get the sizes right in the first place:
-- the disk is a multiboot system disk,
-- I use partitions to organise things to make image backups smaller and faster,
-- some areas of the partitions store unmoveable files,
-- partitions cannot be extended to the left without using a third-party tool,
-- I did read (in "Windows 7 in Depth") that, once shrunk, the OS partition cannot be extended; see here: Extend Boot Volume