Anyone have a good ink that they've used with the Montblanc 149 Calligraphy/Flex nib? Something with a good flow, that can stand up to some slight flexing that occurs while doing generally daily writing. I recently got one of these and I seem to have some skipping on some of the downstrokes of some letters (T, L, B, Etc) periodically while taking notes. It almost seems like the feed is having issues driving enough ink to the nib at times but then recovers quickly.