Sounds like you're making good progress and collecting enough information to give you confidence as you move forward. Regarding Oxybutynin, an NIH article stated that many patients start to experience the effects in 2 weeks, with the full effect in a month. The most frequent side effect was a dry mouth, with the interesting caution to brush your teeth more frequently because the dry mouth increases the risk of decay. Keep us up to date as you learn more!

Best wishes!