The 2 Tests are to Dial in the Horizontal Expansion and the Horizontal Hole expansion.
The 2 versions have:

• 40mm Plug-Size, 40mm Hole-size, 60mm Frame-Size
• 20mm Plug-Size, 20mm Hole-size, 40mm Frame-Size
  Of course, you can adjust the size in Cura if wanted...

Be sure to place the Seam in a way to have it in a round part of the plug to not being bothered by blobs from layerchanges. --> Place it at 45°, 135°, 225° or 315° / Top-Left, Top-right. Bottom-left or Bottom-right in Cura

Start with all 3 Expansions @ 0.0mm.

• Dial the outer dimension first (Horizontal expansion)
• Then, Dial in the Hole-Size (Horizontal Hole expansion)
• Lastly (Can also be done during the other 2 tests) adjust for elefants foot (Initial Layer horizontal expansion).

To not being bothered initially with elefants foot, you can fit them / test them TOP to TOP: Flip one part after printing and match them with chamfered sides.

I often print them with 0 Bottomlayers and 0 Top layers...

Oh... cura has Hole expansion in RADIUS and not Diameter. So, if your hole is 0.3mm too small initially, go with 0.15mm hole expansion.