Need help with a few questions

[DaDelvi]

So I saw this setup https://i.ytimg.com/vi/bB4fh1dSEt0/maxresdefault.jpg and i loved the ultra wide monitor and he's running Windows 10 but also on the left of the picture he's got a MacBook which I have. I'm wanting to get a really nice monitor large to support both (not at the same time so to speak) my gaming rig and my MacBook.  How would that work as far as I want to switch over different OS Rigs? What monitor would be beneficial for both what sizes? and 1080? 1440? 4k? 24"? 27"+? I just want a middle ground so they both look decent and somehow can switch over when I can. 

[Damascus]

How powerful is the mac and what are your PC specss?  Also, ultrawides come in 25", 29" and 34" with a resolution of 2560×1080p or 3440 x 1440p flavors

[DaDelvi]

It's the base model 12" MacBook which says: 

 

Retina display

12-inch (diagonal) LED-backlit display with IPS technology

2304-by-1440 resolution at 226 pixels per inch with support for millions of colors

16:10 aspect ratio

Supported scaled resolutions:

• 1440 by 900
• 1280 by 800
• 1024 by 640

Dual display and video mirroring: simultaneously supports full native resolution on the built-in display and up to 3840 by 2160 pixels at 30Hz on an external display, both at millions of colors. 

 

I dont mind 30hz while I'm using my MacBook. 

 

My gaming rig rig is an i5 6600K with a 1060 6GB which is running a 1080p right now. I want to be able to use 1 monitor for both. I was thinking an LGUD88 but for someone who is experienced in resolutions what would be best of both worlds?