The Cordano Co. has been fine-tuning its plan for a high-rise at 831 L Street in downtown Sacramento, and is closer to making an important decision – whether to build a residential tower or an office building on the property. The company earlier looked at an office building for the site, but with other high-rise condo projects canceled or delayed, including The Towers on Capitol Mall and Aura, The Cordano Co. started looking at a 15-story, 173-unit condo tower. The company is also considering at a 13-story office building for the site, but the downtown office market has been weak during the past several months. The company has talked about both plans with the Sacramento Design Commission.