Oversized is a cut, not a size. That sounds like a small distinction, but it decides whether an oversized T-shirt looks intentional on you or just big.
Here is the difference. If you take a regular T-shirt and buy it two sizes up, every measurement grows together. The shoulder seam slides down your arm, but at an angle that was drawn for a shoulder, not for an arm. The collar opening gets wider and starts to sit away from the neck. The sleeves reach further than they were designed to. You end up with a larger version of the same proportions, and the proportions were the thing you were trying to change.
An oversized pattern is drawn differently from the first line. The shoulder is dropped on purpose, so the seam is meant to sit down the upper arm and the armhole is shaped for that position. The body is cut wide relative to its length, which is what makes it read boxy rather than simply long. The collar stays in proportion to your neck instead of growing with the rest of the shirt. Nothing about it is a normal tee scaled up. It is a different set of decisions.
That is how DROP 001 is cut. Oversized and boxy, with dropped shoulders and a tight rib crew neckline that stays close while the body stays roomy. The contrast is deliberate. Structure at the neck, volume through the body. The cut is unisex, one fit, sized M, L and XL.
The fabric is the other half of the fit. For the silhouette we wanted, 280 GSM gives the body enough structure to support the boxier shape. The weight and the cut work together, which is why they were treated as part of the same garment rather than separate specifications.
How should it sit? The way the size guide describes it. Wide across the shoulders and long in the body, with the seam falling off the shoulder and the body hanging straight rather than tracing you. It is not a fitted piece, and that is the design, not an accident of sizing. If you put it on and there is clear room through the chest and the shoulder seam sits down your arm, it is doing what it was drawn to do.
On sizing, use the measurements rather than your usual letter. The size guide lists chest, length, shoulder and sleeve for every size, measured flat. As a reference point, the M measures 60 cm pit to pit, which is 120 cm around, and 72 cm in length. The method that actually works is the one the size guide suggests. Lay a T-shirt you already wear flat, measure it, and compare. Every size is cut oversized, so you are choosing how much room you want, not whether it is roomy.
And to be clear about who this is for. If you prefer a T-shirt that follows the body closely, an oversized cut will not give you that in any size. That is not a flaw in either direction. It is a different silhouette, and DROP 001 committed to it fully, because this garment is meant to be worn as the piece, not under something else, and this shape carries it best.