For most people two weeks after you stop bleeding would be too late (but depends on your cycle - it would work if you had a short bleed and a longer cycle). Your estimation is better but if you are actively TTC then regular DTD is the key - not just saving it all up for a couple of days there in the prime time.

Remember that in optimum conditions the boys can survive for 5-7 days so you can have a lot of fun giving them a head start