Man I remember when P60 dropins were popular. Nowadays you have such a large variety of production lights and the complete lights are even cheaper than the dropins back then. :o
If only the x45 came in a version with a deeper reflector. I really like the traditional spill that goes right in front of your feet. But I guess with such high output the MT09R is much more practical, because you don't blind yourself so much?
Nah you are not really losing anything, because the GAs will have a higher voltage sag under such heavy loads. So in the end the VTC6 even at 4.1V will probably last longer until 3V than the GA would. Of course you can safely use the VTC6 at anything below 100% at 4.2V
I talked to Vinh about battery choice when I bought mine. He doesn't recommend using unprotected high current cells. It's a gamble because the TN40vn draws an enormous amount of current for the XHP35s and depending on the individual emitter, you might kill one. I charge my VTC6s to only 4.1V...