I think i didn't explain myself properly, sorry about that.
The ultra x12 in extension mode ( 1 port) is more than enough extension for me(for now anywas

).What i meant is would i have enough headroom with duals(x12 or vtf2mk5) setup in 1 port mode?
how would dual x12/vtf2.5 in 1 port mode compare to 1 x12 dual port mode in terms of headroom?