To add a home-field/court/ice advantage term to the log5 formula, plug the expected probability of a home team winning an even matchup (for instance, .60 for the NBA, .55 for the NHL, .54 in MLB) into the following formula:

((Team A win%) * (1 – Team B Win%) * HA)/((Team A win%) * (1 – Team B Win%) * HA +(1 – Team A win%) * (Team B Win%) * (1 – HA))

Where Team A is the home team, Team B is the road team, and HA is the home advantage.