Inspired by iomaa's idea, this is my version in Vase mode (Spiralize Outer Contour mode in Cura). This would significantly reduce print time and filament. I slice it in Cura and completed the print within 2 hours and only 14g of filament was used.

Pay attention to the slicer settings below. Those are Cura terms. I have no experience with other slicers.

• Spiralize Outer Contour: enable (required)
• Layer Height: 0.12 (recommended)
• Bottom Layers: >=10 (actual requirement is layer height x bottomed layers >= 1.2, I used 14)
• Line Width: 0.6mm (increase for tighter fitting)
• Flow Rate: add 10% (increase for tighter fitting, my measured flow rate is 92% and I used 100% for this)
• Printing Temperature: 5-10 more than usual to improve layer adhesion, I used 235 for transparent PETG

I always increased flow rate make sure the shell stick to the base in Vase Mode. You may print the test unit to check the fitting first.