Aero 1930s Halfbelt Slim Fit / Luftwaffe clone planned

[Bonneville]

This will be an interesting jacket and look forward to seeing it when it arrives. What would be the reason for opting for 'true two piece sleeves' compared to another sleeve variation, 3 piece I presume. Does one sleeve style provide something of benefit over another?

 

[Rudie]

I want the sleeves to be slim, not baggy. Jan suggested the two piece sleeves would help to get a narrower upper sleeve portion. Plus, I like the look.