Unfortunately, this is the only angle I photographed, but for future reference, could you say what angle/part of the anatomy would have been additionally helpful to make at least a Genus determination? Thanks!

for most of the caddis families you will need a good look at their private parts to determine genus/species.

thanks for the info on that. it seems that their wings are typically tented over the relevant area, so unless I flip 'em over I'm unlikely to get the critical shot. I had hoped the wing pattern, venation, and possibly some closeup of the head/antennae (to count segments) might do the trick.

because of their generally drab nature (good for hiding) not enough of the caddis with good photos have been kept so that the genitalia can be examined so a picture/species correlation can be made. Most people who take great pictures don't keep the specimens.