Based on these pictures, does it look like spoke washers should be used in this wheel build?
From what I read on a couple web pages (https://sheldonbrown.com/wheelbuild.html#washers and https://roadcyclinguk.com/how-to/maintenance/winter-wheelbuild-part-seven-spoke-washers.html), spoke washers are used if the hub flange is too thin to support the j-bend sufficiently.
In my case, without washers, the space between the spoke (just after the bend) and the flange made me think that washers may be needed. It looks similar to the picture in the 2nd link above. But when I add a washer, the spoke still doesn't sit flush with the flange; in fact, it seems like the spoke wants to exit the flange at a worse angle than before (pointing farther away from the rim), so I wonder if the stress on the j-bend may actually be worse with the washer. This is with a SRAM 900 hub (aluminum) and Sapim Strong 13/14 gauge spokes. The washer is 0.6mm thick. Perhaps the shape of the bend on these particular spokes is a little different than most, making it look unusual even if it's not a problem.
Note that in these pictures, the spokes aren't fully tensioned yet.