A mile or so won't make a big difference to us. The instruction to leave a fix on a heading will be done for sequencing, not for separation purposes. Some aircraft will turn a mile or so early, others run over the fix and turn, so we're not relying on it for separation. (Maybe other ATCOs can recall what aircraft type had the reputation for turning early at waypoints - either the E145 or A320).
030 off DAYNE is just a downwind heading so the real fine-tuning will be done with the turns to base and final.