Question about building a ROP light

Hello, I'm super new here, I joined a long time ago and really haven't posted too much. I was reading on a knife forum about someone building a ROP maglight so I Googled it. I found this page HERE, but it is only about the 2D maglight. I have a 4D maglight and I wouldn't mind doing something similar with it. Is this possible? Could I use all the same parts as the 2D conversion and just get two battery adapters instead of one? I'm an idiot when it comes to flashlights and electronics/wiring, but I do love getting new lights that are brighter then what I currently have. My maglight is the emergency light that is beside the bed at all times, it is also a LED one, but I believe you can swap the LED for a regular bulb as well.

As long as your 4D has the removable PR LED module, it will work fine as a base for a ROP build. Just about any C or D cell Mag can be made into a ROP, provided the batteries provide voltage in the appropriate range. Most ROP recipes you'll find here are based on 6x 1.2V NiMH rechargeable cells (7.2V total) or 2x (3.7V) Lithium rechargeable cells (7.4V total).

A 4D makes a great host because it can fit 6x SubC NiMH cells, and there are lots of high-current and high capacity SubC cells available. Just follow any of the other recipes for modifying the head (glass lens, metal reflector, bulb), then use a length of appropriate diameter PVC pipe, rubber hose, whatever to keep the cells from rattling around and modify the tailcap so that the spring seats all the way to the bottom and you should be good to go.