Here’s an idea: You might have people who won’t approve if they feel they are being asked to vote on something a bit vague, without all the specific details you would have once there are architect’s drawings or engineer’s reports. Perhaps it would be a better strategy to ask to have the matter on the agenda just for discussion, not for a formal resolution of in principle support. If it seems on the night that there is broad support, you could ask for a ‘show of hands’ ‘just to get a feel for whether the proposition is likely to be supported, subject to returning to a later meeting with all the relevant documentation for formal approval’ etc. IE look humble and reassuring. Let people have some time to get used to the idea. Make them feel consulted. Talk to as many of your neighbours as possible well before the meeting because many won’t read meeting papers until the last minute. If lots of people go in feeling already reassured about the idea, it is less likely the meeting will veer off course with one or two loud outraged people and everyone else, who might have supported, sitting back silent, confused and slightly gob-smacked.