cage sizes

[Gaboon]

Im going to be building some cages for my 3 snakes which are:

1 male *Ball python*
1 male *Irian jaya python*
1 male *Borneo python*

I asked in the past would 3x2x2 cages house these snakes and the answer was yes but now that i think about it does a BP and a borneo really need 2' high cages?

If i must i will make it 2' high but i dont think they would use the extra head room or am i wrong?

If not 1' high then what about 1'/6" ? Space is not really a issue or price so if they need 2' thats ok but i just dont see the point in bulidng something bigger than the snake will even use.