Hi Craig. I would add that it may be useful taking a look at ETD or Exoclock to give you an idea what observers with similar equipment are achieving. On the ETD planner you can also filter possible targets by mag and transit depth which may help with selecting targets. On paper HAT-P-20b looks like a good target but it’s worth noting it has a mag 12.5 star just 7arcsec away which you’d need to seperate in your photometry.
Mark