The goal is not to screw things up on the checkride, but if you have to, let it be the highwork as opposed to the pattern. The IP will be alot more forgiving if your approach turn stall is hosed than if you cut off your interval in the landing pattern. There are two things they are primarily looking for on your Contact Checkride in Primary: 1.) Make it to your area and back safely without getting lost, and 2.) Be able to safely land the plane.
If you can nail those two, there's a 95% chance you will pass the 4390. If your highwork suffers a bit, oh well. You'll get plenty of practice in aerobatics. Have fun, and definitely get enough sleep. Good luck.