Consider offering the property as a "fixer upper", no matter the condition. It'll attract a lot of buyers who always think they can get a deal and start the offers coming in. Any low ball offers can be countered or held back as a plan "b".
You want to list it now (as soon as it is ready), and sell it ASAP.
You did not mention the List Price to Sale Price Ratio of those four sold homes. Can you find out?
Homes that sell in the first 30 days usually sell for the most net to the seller.
If I were your Realtor, I say get it sold as soon as possible, keep escrow (no property is really SOLD until escrow closes, so just because a property opens escrow does not mean it's really sold) to a normal length.
I would suggest renting back with a provision to extend if your new home is not ready. How is the builder's track record on timely occupancy? What if it snows and no one can get to work?
So far our advice is the same. Put it on the market now. It is easier to negotiate for more time, without losing money, than to worry about it not selling at all! As we close in on the holidays, people who don't have to move will put off looking until after the holidays! Put in on the market now!
First, please make sure the 4 houses you mentioned are recent sales as market has turned recently, both due to real estate supply and demand in general and also because of problems with lenders. If the sales are not recent, then we will need to adjust the dates.
Assuming the 7-17 days are current, and we can use the numbers, then we can count the days again. To get top dollars, you will want to have your house in the tip-top condition Let's say it takes two weeks to get it all cleaned up, declutter; stage (if you want); landscape and what not. Add 2 weeks to get into escrow. Now you have 2 months before moving into your new home.
On the escrow, you might want to negotiate a 60 days (or a date works with the 84 days) close, which is not uncommon. The question is you can find a specific buyer that can work with the 60 days, but that should not affect the offering price.
If I was you, I would not postpone the sale on purpose because of worries about the price. 7-17 days to get into escrow is pretty fast in today's market, and I would not want to wait for it to slow down. It's easier to negotiate a move in date than it is to find a buyer. If you can't find the buyer before your new house is ready, you will be looking at carrying two mortgages, I presume. You will also be looking at September to November and then then you push into Thanksgiving and Christmas; so I won't wait too long to get it going.