He has 12 plaid shirts in total. Most of them are long sleeve, just 1 short sleeve because long sleeve easily matches with both formal & casual looks.
He prefers small plaid more than the large one coz it makes he looks thinner and classier.
About colors, bright colors always make you look younger, more refreshing while the dark ones will inspire you to feel like a gentleman in special situations that you need to show your professional look & feel.
In terms of form, make sure that it’s not too tight or too oversized with your body. When fitting a shirt, beside the length of center back & your shoulder , feeling comfortable when moving your arms up, there is one tip for your reference: the distance between your hips & shirt should be around 3cm, . This will make you feel comfortable when putting the shirt in or out the pants but still look clean & gentle at the same time.