Hi!
you can do this:
Create the cone first, then you use the "unfold" tool to Flat the part. (Unfold, NOT the same as Flat Pattern)
Do the holes you need, use "Cut", "Pattern", etc
Finally use "refold" tool to have again the part folded.
Did you find this reply helpful ? If so, use the Accept as Solution or Kudos - Thank you!
CCarreiras