Gas Fireplace: How do I arrange rockwool and logs for maximum heat?
The "optimal" placement of the logs is that shown in the manual for the unit.

Rearranging the logs doesn't change the amount of gas being let through the gas valve, which is the only variable that will change how much heat the fireplace produces.

It can however cause the unit to burn dirtier and create soot, if you place the logs in a way that causes impingement (flame touches them, essentially).

Chances are it feels warmer now because you've moved the front log which is allowing more "radiant" heat to come straight into the room, but the unit would not be creating any more heat than normal.