Do you have a copy of the EW handbook? First, need to be sure you have an EW clutch. Douglas constantly made running changes to the flywheel clutch and a lot of bits and pieces swap about. In this post there is a section view of the typical EW flywheel clutch-
https://www.douglasmotorcycles.net/index.php?topic=5368.msg19430#msg19430While the post is about the CW clutch, the illustration shown is EW. A CW clutch can be seen here, for comparison-
https://www.douglasmotorcycles.net/index.php?topic=5366.msg19455#msg19455Eventually they got rid of the drive dog and moved to drive pegs on the pressure plate, which project through the face of the flywheel. One of these later clutches could have been installed on your EW. The CW used a smaller flywheel taper, so you probably do not have to worry about that one.
There are two sets of rolling element bearings in an EW clutch. The 1/4 x /4 rollers are the radial bearing and take the chain load when the clutch is disengaged. As the race for that is integral with the sprocket and the pressure plate hub, you probably are not referring to that one. The other is a ball thrust bearing for lifting releasing the clutch. This uses 3/16 balls, but a 3/16 thick 'Oilite' sintered bronze oil impregnated bearing works well too if the thrust faces are pitted. The cage for the balls should be just under 3/16, of course. With the clutch engaged, the thrust bearing should not have any pressure upon it. For maximum lift, it should have the barest amount of clearance feasible (minimal slack in the clutch cable), much like any other motorcycle clutch.
-Doug