1, no it means it is low power bulb, (11w) another bulb in the set is high power 24w.
2 no, you can't use standart, they don't have enough power for the bulb. it will be very dim and yellow.
3 high beam bulb uses even more power than low beam bulb, standart batteries don't have enough power for low beam bulb, let alone high beam bulb.
4 it means 2 li ion rechargable cells. he assumes your lights are maglights, but i don't see any indication in your 1st post that lights are maglights. spacer and tail mod only applys if your lights are maglites.
also with heat those bulb generate (low and high) you would need mettal reflectors and glass lenses, plastic ones will melt or deform.
your bulbs are led retrofits, they are less bright that regular bulbs you have now. they do last longer from a set of batteries. those bulbs were relevant many years ago when leds were very new thing, now for the money you spend on retrofiting your lights you can get good new led light.
my advice, don't bother, it ain't worth the money and effort. leave those lights in a drawer (or garage, or kitchen, or.........) for emergencys, and get new led light.
:thinking:
