By spotting, do you mean for distances over 150'? If so, you may want to consider a non-LED based light. Incandescent lights will throw better than LED's in their current iterations.
If you were to buy one light, I would certainly recommend the L7 over the Gladius because the output of the Surefire L-series lights (Except for the L1) is considerably greater than the Gladius.
In a comparison between the L5 and the L7, the output and performance should by very similar with a slight edge in throw to the L7 (as it appears to be patterned after the L6 which has a deeper and possibly larger diameter bezel). If you don't mind carrying a larger light, the L7 would be a nice choice. It is not as "sexy" as the L5 however.
Happy Easter!
-Goatee