From most to least desirable covers
1. The Beck cover has a Hayes block of four. It is the only Hayes FDC with more than one Hayes stamp on it.
2. The Ward and Strasser covers. These are the first FDCs to have the rubber stamp imprint of the Philatelic Stamp Agency. Some of them also have the wax seal of the Department of Stamps (Ward and at least one of the Strassers). Since Strasser was the only person to receive FDCs from Fremont and Washington, an exhibit page with his covers from the two cities would be impressive.
3. All of the other covers canceled later than 10:00 am. These covers are either special delivery or registered covers with the proper usage of the 11-cent Hayes to meet required 12-cent frankings. All have backside postal markings.
4. The 10:00 am covers, of which all were serviced by Worden. A number of them were initially unaddressed (hand backs) and had addresses added later. Even though the covers addressed to Worden are generally vf, their quantity and similarity tends to degrade them. The count of 60 Worden covers is a reasonable estimate.
Plate numbers are not found on any Washington covers.