It would take a lot more information about your specific situation to really offer useful advice. It may also be a case of over thinking your situation. If your home is on the market now, and another home that you want to purchase is also on the market, I would focus on achieving your goal of buying the house rather than getting caught up in the timing. For the average buyer/seller the timing question won't make that much difference and if you are one where it would, I'd consult your accountant.
One last thought, with rates being so phenomenal right now and the uncertainties of an election about to take place, I would be inclined to encourage a sooner move rather than later. Who knows where things will be after the first of the year?