best led upgrade for lumilite 4600, fulton mx-991/u, maglite 2d

#1 What would a good led upgrade for a lumilite 4600 lantern. I was thinking an everled, tektite lpr-4, or a terralux tle-1f. or am i better off keeping a kpr113 buld in it? I plan on using a 6v lantern Battery in it.

#2 I also have a fulton mx-991/u light from my brief stint in military. currently it sports a maglite 2d cell bulb. Would any of the 2 cell versions of the above leds work good in it? would would be the brightest available?

#3 I currently also have a red 2d maglite i would like to upgrade. I was thinking of getting a 5 watt led for it, such as a TerraLux Ministar 5 TLE-6EXB for it. I looked around and couldn't find anything brighter. I have also a pair of Accupower low drain d nimh cells that i use in it.

Any helpful suggestions/info would be greatly appreciated.

Im modding my fulton with 2300 Mah NiMH AAs (x6) and a 6cell Xenon bulb for starters. I'll play around with that, get the battery pack dialed in and working well, and from there perhaps a more extensive mod with LED and DC-DC regulation.

I'm too new and really dont understand enough to go hog wild yet, so I'm sticking with a simple incandescent mod for starters. I already have the cells and I can use the programmable charger from my RC hobbies. I figure if I screw up I'm only out the $2 price of the bulb.

that sounds like a good idea, i would like to find a led that could drop right in that would take 6 cells. I to am a rc modeler, i have a multi cell battery pack charger mrc 959, and a maha 808 charger i could use. i do have a bunch of 2100mah aa energizers laying around. those could be put to good use ,a little soldering and they would be good to go.