I bought an Economy handle for the shower, only to find it didn't come with finish flanges. I looked and couldn't find 1.25" (86mm) split flanges that worked and didn't cost too much.

I had some grey PETG which works well, it's durable and prints well.

Creality

Ender 3

No

No

200

35% Gyroid

Print it face down, it doesn't need supports

I put mine on while it was still hot, split it and go slowly on sideways. I tired concentric and it broke. Gyroid infill was strong enough at 35%. After it is on you will need to bend it back the other way so one side doesn't stick out. You can calk it in place if you would like.

Fusion 36) is my go to cad program.