Drafting Wovens without Closures? Sewing Machines Parts and Sales in Los Angeles

Hi friends,

I'm working on drafting my own patterns/slopers from my measurements. My most used patterns are woven shirts that don't require any closures (like zips or buttons) to help you get them on and off. I'm thinking specifically of patterns like:

Grainline Scout Tee

Seamwork Akita

Grainline Hemlock

Colette Sorbetto

My question for more knowledgeable sewists is… what makes these patterns work? How is it possible to take them on and off without the closure? Does it have to do with the size of the neckband? The ease in the shoulder area? I have been researching "Woven without closure" or "drafting wovens without closure"… is this the right way to describe what I'm looking for?

I'm looking to be able to make my own woven patterns similar to these based off of my measurements because the XS offered in these patterns above is often too big for my frame. Any help would be greatly appreciated!

Edit: Formatting