Hi Not So, don't overthink this, you will have a great nudist experience whether you go in March or April or December or June. The comments about textiles on the weekend are reflective of the visitors that come then, and not of any unwritten rule. Many times they are with a group of coworkers/classmates/relatives who they don't want to get naked around. No one will care about your lack of attire. Weekends and weekdays, I've been to DC many times, and every time my clothes come off at Bowen Ranch and don't go back on until I'm driving away. I camp naked at Bowen, you won't have any problems with Mike. However, Bowen is the high desert at about 4500ft, so be prepared for severe weather, it can get very cold/windy/rainy/snowy even when it is beautiful at the springs. There are no amenities at Bowen, so bring enough food/libations/firewood/TP to last the length of your visit because the nearest store is not near.
Not only will you be fine, you will wish you didn't live so far away so you could visit more often. Write a trip report here after your visit.