I see that there are two sizes - medium/'standard' and large/full-size, ignoring the "realo" piston filler model. I am not familiar with these sizes, but am familiar with the Sapporo standard (or Pro-Gear slim, distinct from Sapporo mini) and Pro-Gear standard sizes. My question is what is roughly the size of the 1911 medium/standard model when compared the Pro-Gear standard? Are these two similarly sized pens? Thanks, and I apologise if this has been answered in the past.