In this article+
01
Start with cloth weight
Light moleskin can cling and crease like a shirt; very heavy moleskin can stand away from the body. Look for a substantial but flexible cloth that bends easily in the hand and returns without remaining sharply folded.
02
Fit the shoulder first
The shoulder seam should sit close to its intended position and the upper back should remain smooth when your arms rest naturally. Sizing down to remove body volume often creates pulling across the shoulder blades.
03
Check the back from the side
Turn sideways and look behind the armhole. Excess cloth that forms a rounded pocket or shelf will become more visible once the nap catches light. A centre pleat may add movement, but it should close again when you relax.
04
Control the hem
Most overshirts finish around the upper-to-mid fly. Short bomber-like cuts may stop higher; longer workshirt cuts can reach the lower hip, provided the hem does not hide the trouser rise or bunch above the seat. A stiff, wide hem can exaggerate ballooning.
05
Wear the intended layer
Try it over the tee, polo or fine knit you will actually use. Button it, reach forward and sit. If it looks clean only when empty or only when left open, the cut is not doing the job you need.