It seems to me, that the qpid-config --file-size parameter's help text uses incorrect units. It shows:
--file-size=<n> File size in pages (64Kib/page)
which would indicate that 24-pages (the default) would yield 192KiB journal files (24 * 64 / 8). But instead, the journal files I get are ~1.6MiB, which would suggest that the 64Kib is meant to be 64KiB (ie Kibibytes instead of Kibibits).