Using worsted yarn, not DK. I expect it to be much larger than pattern.

Errors in the pattern, I’m guessing during the translation from Dutch to English. I made corrections to Rounds 1 and 4.

Round 1 should be:
3ch (counts as 1dc), 14dc in ring, join with ss. (15dc)

Round 4 should be:
3ch (counts as 1dc), 1dc in same stitch, 1ch, 2dc in same stitch, 1ch, skip next 2 stitches, (2dc, 1ch, 2dc) in next stitch, repeat from * to * around, join with ss. (15 groups)

Modifications:
I did the slipstitching with a 6mm hook to be sure it was very loose.

Because of the size of the yarn, I eliminated rounds of the pattern and adjusted the number of dc in the spaces on the last round.

I added chains to the slipstitching to add length so that the stitches wouldn’t pull and warp the project.

I used a smaller hook for the smaller sizes.

Since I’m just going to use these as pan protectors, I made them single layer.

NEXT TIME:
In order to prevent the waviness of the project, I will start with fewer stitches. 15 is a lot. Maybe I’ll do 10, then 20, then 30. It’ll mean fewer petals but I’d prefer that over it not laying flat.

Other notes:
The slipstiching was very fiddly. It’s a cool finishing look, but I really struggled with it.