Giveaway round 3

Hello my friends.
In round 2 we managed to calculate budget for digging 3 water wells (please, check my previous posts to get up to date).
This way we have necessary money, but we blocked most of superblock budget. We don't need all that money now.
Firstly, setting budget proposal for "one off " payment straight away rising alerts, especially if submitted by person without previous history of community works. Even nicely written budget proposal may be viewed just as a scam. So, what's the answer? Stages!
Much easier is to get that budget in stages, "easier" in more ways than you think.
Let's continue with our (just theoretical) water wells. Way better option would be to set reoccurring payment. Let say, we expect that project will take 4 months to finish. All we need then is payments of 200AGU from next 4 superplocks. Masternode owners can vote now with bigger confidence, as they risking less money and will be able to monitor progress of the project reading frequent updates on the website. If the project progress is not satisfactory or even worst -abandoned, they can withdraw their approval for that budget by changing their votes. At any time they can change vote to "NO" on that budget and when difference between Yes and No drops below 10% of all masternodes, get it blocked for remaining funding rounds.( I wish, that political voting will be as easy as this).
Question 3 for 350AGU:
Assuming, that Agouti has 450 working masternodes and our water well digging budget proposal already has 30% of YES votes, what's the minimum number (not%) of masternode NO votes necessary to block that project?