Vertex tool issue

[KubeDawg]

So I've tried numerous attempts to create something nice looking for my map but hammer just doesn't seem to like me.

Here's an example of what I'm trying to create:

Firstly, I make a cylinder with 8 sides and cut it in half. To make things easier for the vertex tool, I cut the cylinder into 4 wedges:


After that, I break out the vertex tool and start making changes to the top portion of the triangles:

which then ends up looking like this:


But as soon as I save my map, exit hammer and open it up again, this happens:


Notice in the 3rd screenshot in the top view where they connect, the top and bottom parts of the wedge are 3 units apart diagonally. If you look at the distance between the two middle wedges, the distance is 4 units horizontally. This, to me, is what is causing the problem because they are not the same length and hammer is auto correcting what geometry it can handle. So when I open hammer after saving, it's corrected the angle of each wedge so the top and bottom parts of the wedges share the same angle. I'm using the smallest grid size so it's not possible for me to try to match up the angles more perfectly.

Even if I match up those angles again so they look like I want them to, restarting hammer only shows the same issue again.

Is there any way I can get around this problem or am I sol?