I would make a phone call to Potomac Tracon or Dulles Tower to find out the ideal time for arrival. Give them your "N" number and tell them you would like to fly the Jasen2 arrival if possible. That way they will be expecting you and will probably be more receptive to your requests. Also, be familiar with the ADIZ and FRZ procedures in case you need to bolt out of IAD under VFR.