I always model, in model space - full size. Generally, there is no need, as far as I can see, to scale anything during the creation process.
So, if you save and send a .dwg file to a client, it should remain full size i.e. 1:1. They can then scale as necessary, if they so wish.
I hope this helps.
You can design without engineering, but you cannot engineer without design.
Using Win 10 with Designer 2016/2017 and TurboCAD Pro. Plat. 2018/2019 + Lightworks (64-bit versions) + AnimationLab 5.2.
Windows 10 Pro 1903 (Build 18362.476) 64-bit