Independent commissioners Andrew Henderson and Christine Kelly heard on Friday that the future of the historic St John's Presbyterian Church would be in jeopardy if the hall was not approved.
Otago Foundation Trust Board counsel Vanessa Robb, planner Gemma Pemberton-Smith and architect and heritage specialist Jackie Gilles answered issues raised in Lakes Environmental planner Hannah Afifi's report.
They noted all door and window joinery would be painted timber, instead of the church-preferred and tougher aluminium.
Glazing had been changed to two separate windows and one set of double doors.
Coloursteel roofing would be in a low-gloss finish that would dull in two years.
The hall would be built a further 1m back from the church and its colour scheme would be "sympathetic but recessive" to the historic building.
A time limit on parking did not appear to be needed, the commissioners heard.
It would be out of Arrowtown's character and a burden for the Queenstown Lakes District Council to monitor as the town had no parking warden.
Arrowtown residents Bryan and Helen McGillan submitted the hall proposal did not legally protect the historic holly hedge on the Berkshire St frontage from future development.
The hedge mitigated the hall's impact on the residential area.
If it was removed, the amenity of one of Arrowtown's entrances and exits would be affected.
Although it was highly unlikely the 1.8m high hedge would be removed, Mr McGillan asked the trust to register a covenant to protect, maintain and repair it, if needed.
Mrs Robb said a hedge protection order and advice note would be attached to the consent.
Only two of the nine parties who had given their affected party approval were still to sign off on the new amendments, commissioners heard.
Building committee chairman Bruce Patton said the modern facility would be the catalyst for new outreach programmes by the congregation, that would secure younger support for church upkeep.
Hall hiring to the community would be crucial to fund ongoing costs.
Hall design had been "an exercise in compromise" under district plan, zone and Historic Places Trust requirements and following community, parish and Presbyterian consultation.
Mr Patton said the existing hall, which was part of the former Millers Flat church, was nearly 140 years old, was crowded and uninsulated and had 50-year-old facilities.
An appropriate site near the historic cottages on Buckingham St and the old hall's relocation will be subject to a separate resource consent, Mr Patton said.
Building committee member Noel Dunlop said $726,000 had been raised for the development, but the costs of the resource consent process had been "staggering and frightening" to parishioners.
The consent application cost more than $66,000, not including Friday's hearing.
Parishioner and supporter Brian Bayley said there was no need for large numbers of off-street car parks should the hall be approved.
Arrowtown could absorb many vehicles on grassed verges and the need for off-street parking was "a myth in the mind of well-meaning but overly conservative planners", he said.
The commissioners reserved their decision.
