Lamy Rollerball Refill Review - M63 vs M66 "quicky post"

This is a quick post in reply to our friend Azizah over at Gourmet Pens from my last review about the Lamy Swift Rollerball.  I'm so glad she commented because there are two Lamy rollerball refills that I've used: the M63 that fits the Safari and the M66 that fits the Swift.

It wasn't until I did a side by side comparison of the two did I realize that the M66 of the Swift is considerably smoother than the M63 of the Safari.  If I were to make a recommendation on smoothness alone, I'd say go for a Lamy that takes the M66.  

Visually, the refills seem to put out similar ink flow, but I'm going to let the pictures below show the line comparisons...