Since the introduction of these kits the WIP A20LDX has been retired. It functions, but I don’t like it - swing by that thread for more details.
In the meantime I’m retracting my offer to build drivers for now, but also dropping the price on these kits! The clearance price is $25/shipped in lower 48.
These kits are still 100% workable, the included DD driver will allow you to build either a Lux-Pro 2D or Maglite 2D. If you want to build the linear driver that’ll work too, but understand it’s limitations before committing.
In either case you may end up needing to do a DIY bore on your light, depending on the size of your cells and the ID of the light. See here: Old-Lumens - Boring a Maglite D body for 4AA - with a home made drill press and a bi-metal hole saw.