Why are you "already selling a property now"?
Right now I feel like I would need to stretch my parameters and settle for a barely okay deal to buy another unit. With the possibility of a down turn I want a solidly good deal. I plan to hold out for the cycle to turn unless I am surprised by a good deal. So my real estate investing is stalled for the moment. If the economy cycles every 8-10 years, its time. This last week in particular the stock market has been very volatile which probably means nothing but makes me a little nervous. I'm not worried enough to start selling off the real estate portfolio but my cash is waiting for an opportunity and I have a couple units that are free and clear waiting to be refinanced, quite a bit of opportunity sitting dormant. I have been expecting the stock market to drop for over three years so obviously my crystal ball does not work.
If I added in the need to avoid taxes with a 1031 it would shift my need for a really good deal a little further toward settling for an okay deal, just run your number to figure out how much.