MF/HF - when is decision made?

[Grandviceroy2018]

some units can be purchased as EITHER MF or HF (the Theuros offensive spear in the graeoco bactrian and other successor type armies).

the cost is the same.

do you have to announce BEFORE seeing the terrain/opposing army whether they will take the field as MF or as HF, or can you decide during the deployment phase?

regardless of the answer (my personal belief is BEFORE but i could be wrong) is there a page ref in the rules to show that to someone?

[nikgaukroger]

When you choose the army composition before the game/competition. Troops can be deployed in alternative ways depending on preference for that game are specified in lists - see the Alexandrian list for an example.

[Grandviceroy2018]

i see how that applies to that special unit in the alex list (foot companions and hypaspists)

but it does not say anything about WHEN you decide if your THureo/thuro are placed on the table as MF or HF.

so, again..

WHEN do you decide?
-before or after placing terrain?

[nikgaukroger]

i see how that applies to that special unit in the alex list (foot companions and hypaspists)

but it does not say anything about WHEN you decide if your THureo/thuro are placed on the table as MF or HF.

so, again..

WHEN do you decide?
-before or after placing terrain?

And again - when you choose the army composition before the game/competition.

So before you even leave your house to go and play the game you have to decide if you are taking them as HF or MF. This is because the choice represents a fundamental difference in the view of the best representation and not because the troops operated differently at different times - that latter sort of difference is the type covered by list specifications like the example I referred you to to indicate the difference.