Sorry if it is not allowed to post in English, or if being an English speaker makes things more difficult.
わたしの日本語レベルは幼稚園児よりひどい
But I am curious about some things and there are little resources in English or other English speaking users I can talk to about my questions.
I hope it is okay to ask here.

I use metasequoia to create 3D models for use im MMD as .PMD files. Often when I begin to create polygons, I believe I make a very large model in the 3D space. When I try to use the Scale Tool to make the polygons smaller to fit the scale of a .PMD model I encounter problems with the display.
In Version 3.1.0 or similar versions, the perspective would become very stretched or the "camera" would clip into the model making it hard to see. Using "Set View" and changing the perspective often fixed this. But now I am using Metasequoia 4 ver. 7.5 I do not know how to "Set View" with the newer GUI.

But my current problem is that after scaling down the model, polygons display strangely, and I can view faces through others. Such as the mouth showing through the cheek of my cat head model: https://i.imgur.com/yCl4iFv.png
The ear and tips of fur also display strangely. I assume this is an issue with the scale of the model.
When I try to scale it larger to attempt to "fix" this, it does not help.

The camera also jitters and shakes whenever I rotate, zoom, or translate the camera: https://i.imgur.com/2jqYsNN.gif

Thankfully I have a version of this file saved before I tried to scale it to be smaller. And the view is fine.
This is how it should look. https://i.imgur.com/Th71zei.png

But is there any way to prevent this? Is this too small for Meta to display correctly? I will not make something this small again to prevent it from happening.