For this project I used fingering yarn so I needed to had some rounds to make the pincushion big enough:

for the big one, I used the bottom flower pattern and added:
-kfb, k4
-k all sts
-kfb, k5
-k all sts
-kfb, k6
-K 10 rounds
-k2tog, k6
-k all sts
-k2tog, k5
-k all sts
-k2tog, k4
-k all sts
and then I continued the diminution written in the pattern.

For the smaller one, I used the bottom flower pattern and added 1 increase round.