Here is my 1st project....a 3d printed arch.
Daytime: https://youtu.be/Hxy2S2rUM0Y
Night: https://youtu.be/G_NET8RtKeI
I loved the design you linked to and I was going to print it, but I figured I would give it a whirl and I wanted a rounded arch (just looks for Chrismassy), my 1st attempt in tinkercad.
The attachments show the sections and comparison to 3/4" PEX.