The way the legislation is drafted it is contemplated that you call for nominations first, and then the number of EC members is determined, then the EC members are elected. One of the reasons for that is so that you don’t have a situation where you have a certain number of EC members but will never be able to have a quorum.
Refer for example here in Schedule 3 (which refers to the first AGM)
(c) to determine the number of members of the executive committee and to elect the executive committee…
Why don’t you just draft the motion as open, i.e. “That the Owners Corporation determine the number of members to constitute the Executive Committee”, followed by “Elect the members of the Executive Committee”?
As the legislation currently stands you can’t have 12 members of the EC, the maximum is 9.