can we launch a 6.5m there?

My experience as well ... in keeping with the fact that despite the huge size of the harbour there is no ramp I am aware of that ticks all the boxes. ie available parking, all tides friendly, does not require a long trip to open water or no security problems therefore agree with Nick that launching & retrieving a 6 . 5 mtr boat would at best be very ambitious. 

To the best of my knowledge choices close to Tapora would be Port Albert ( tidal & long haul down river to open water ) Stables Landing (could be a problem with shallow water) Mungakura (steep slippery ramp ) Jordan Rd ( a guy I knew used to launch his 6 mtr boat there, but before you even consider it go take a look at the setup, likewise another a bit further on by the concrete bridge ) IMO your best option if available would be a tractor tow to & from Tapora ramp to launch into the mouth of the Port Albert river.

PS Nick presume your interest in that area was related to SWFF ...

if so may be able to give you some info re exclusive access to some territory suitable for swff that you may not be aware of.

Will pm.