Haven't beaten turn 5 yet but for me it helps to simply focus target Twintania at start of battle so I can see the cast bar. About how far to move outside the pit - I hear the sound of divebomb starting or see green icon and move out, hear the sound of her swipe attack and move back already before the divebomb animation has ended to wait on next divebomb.
Also what work for me on timing second set of divebombs as drg - wait for 2-3 sec till tank get hate on Asceplius and use Chaos thurst combo. When the dot of Chaos thurst is wearing out I position myself and get ready for second set of divebombs. I find it a lot easier than any macros etc this way.
