I had the same idea for getting the pond going quick. This ridge in the middle we covered with 3/4" stone with 1/2" pea stone mixed with some crusher screenings. We have our lily pads in pots on this ridge and now feel its ok to dump them out on to the bottom of the pond.
We have found that if you want to catch a feeding fish any time of the day just drop a worm out on this ridge and you have a fish every cast.
As you can see we just rolled all the rock we found when digging into the bottom and added some cement tile. Dropped in a combine tire as well. Little note drill holes to let the air out of any tires you put into the bottom of the pond or they will float.
We left the rest of the bottom clay. Seams to all be working perfectly fine. We are blessed with the best clay you can have so really digging a hole and filling it with water makes an easy pond. We just set the over flow to the water level we wanted.
Cheers Don.
EDIT: at last two pictures are of the pond full. You can see the lily's on the center ridge in the second last picture. The last picture shows the ridge in green. The air stations in blue and the inflow and over flow from the creek in red.