"I can not understand why the Arc has an obvious diamond shape while a Surefire KL1 has a round center beam."
The diamond shape is the characteristic look of the High Dome LS. The KL1 uses a Low Dome Luxeon which has the smoother beam with less of a hotspot than the High Dome Luxeon.
If you don't like the diamaond shape or "circle in square in circle" beam pattern, I am afraid you are not going to enjoy your LSH-P. On the bright side, it most likely will be brighter and whiter than your LS-2. Also, you will find that your LSH-P will have more 'throw' than your KL-1.
If you like the beam pattern of your KL1 more, you should get the LSL-P (also a LD luxeon). It would have a beam like the KL1 but would probably be whiter due to the Luxeons used by Arc.
I have no doubt if you don't like your LSH-P that you will be able to sell it or trade it for a LSL-P. However, the beam may grow on you. I like mine alot. /ubbthreads/images/graemlins/smile.gif
Pat