Just a few hints: If you rate your film lower and develope shorter you might like the results even more as they become easier to print and less grainy. Try 80 ASA instead of 160. To reduce the dust, wet the shower-cabin and let the film dry in there.
To to keep the grain as small as possible two things help with rodinal, first dilute more. Rodinal behaves just opposite to say D-76 with repect to graininess and dilution. Try 1:50. 1:100 may lead to exhaustion. Agfa says to use at least 10ml stock per roll, for what this is worth. They may just be interested to sell more Rodinal.
Keep the temp below 68F. Yes, this an old rule with rodinal. Never drive up the temperature to save time. I have a text-book from 1949 that even asks to develope at 16°C, 18°C being the standard at this time. This guy is a long term Rodinal user and claims that oatmeal-grain and raised temperature go hand in hand with rodinal: http://www.eak-fotografie.de/
If I was still using Rodinal I would follow his advice.