I think 3 or 4
number 3 - looks great, maybe clean up the areas where the flame touches the "L" even run it a bit closer to the "L" and reduce gaps within the flame, even slim the flame up a bit, giving it a bit more curve.
number 4 - also good, maybe offset the "L" a bit to look like the corner of a light box. ie rotate clockwise a little, and maybe give a little space between L and B like in sample 1.
they all look good, I am sure you would clean them up anyway as these are samples, and you have probably finished the job anyway.