Tomy:
Lowering the fuel temp to increase the air charge density will work, and work best in the 70 deg F range. Colder than that and you run the risk of getting liquid droplet mist into the air stream with irregular cylinder air-fuel distribution.
The primary benefit to lowering the temperature is not the air charge (although that is a positive benefit) but that you reduce the formation and accumulation of hydrocarbon heavy ends, semi-solids, and paraffin’s. They tend to form at temperatures of 140 deg f. Some severe cases have resulted in vaporizer stoppage in as little as 30 hours of operation.
Franz