Hi Sebastien,

"Sebastien Vauban"
<wxhgmqzgwmuf-geNee64TY+gS+FvcfC7Uqw@public.gmane.org> writes:

> I'd like to have a couple of different (column) views in my Org file

How about trying this patch which let you have another format in column
view?

After applying this patch, try this.
  M-: (org-columns "%66ITEM(Task) %6Effort(Estim.){:}")

Best,
IP