GW style puddle bases

I use GW style round 25mm wargame bases for my collection of Bones miniatures, and wanted to keep a similar style for larger monsters. That said, I also like the aesthetic of recessed bases... aka puddle bases.

There are many collections of bases here on Thingiverse however I've had issues with all I've tried - most are inconsistent with the design of existing GW bases, some are not even consistent with each other, and many were made using TinkerCAD etc, where the arcs/circles are noticeably