Maglite 2d 2x18650 vs Maglite 4d for TLE-300M-EX

Looking for comparison between the two. What is the optimal setup for something like this? I am not opposed to the size of the Maglite 4d to run this setup with 4x Alkaline D batteries (unless there is a better choice than alkalines for a 4d w/ this LED)

Is there anyone with experience between the two setups?

The TLE-300M-EX draws 12 watts of power on high.

Volts x Amps = Watts

Two 18650 in a series it will draw ~1.62 amps

Alkaline cells are not recommended as they sag too much under load. I've heard it can be done, but dont expect good runtime with them.

so what would be optimal for this bulb?

Here are some possibilities that can work:
2D - 2 x 18650 in series with tube adapter, or 6aa to 2D adapter (series)
3D - 9aa to 3D adapter (series) or 4C cells with tube adapter (PVC pipe)
4D - 4D or 5C with tube adapter

Of course the cells are nimh except for the obvious 18650 li-ion.

Approximate runtimes on high:
2x18650 -0.8 hours
6aa - 1.2 hours
9aa - 1.8 hours
4C - 1.8 hours
4D - 4 hours

Realistically though the light will be too hot to hold past 10-15 minutes on high.

Looking at the options, it doesn't seem like the 2d would be worth the bother for the price. It's currently a 2D Rebel. Would upgrading to the 2x18650 be a real upgrade at all or would just sticking with the 2D's be best?

A 4d for the TLE-300M-EX seems like it is the route to go or possibly a 3d(for the size) w/ 9AA to 3d adapter, but looking at the price between that and a Fenix TK40, the 40 seems to win out...

Pity the malkoff upgrades are awlays sold out. Would the TerraLUX TLE-6EXB be a worthwhile upgrade for the 2d Rebel, or should I just leave it be?

Rebel-based mags (DL in serial number) cannot be used with any of the terralux upgrades. The terralux upgrades only work with the incan-based mags. When the TLE-300M first came out it was pretty good, but fast-foward a few years and currently its just OK if not a little bit expensive. FYI the TLE-6EXB does about 100 OTF, same as the rebel-based mags.

gotcha

are there any type of upgrades worthwhile to do to the new Rebel 2d maglites? anything from battery upgrades (not sure if it would burn out the bulb, etc), glass lense, etc?

You cannot use more than 2 cells (2.4 to 3v) for the stock 2D rebel light, you will fry the circuit inside the LED pill. You could replace the lends with a UCL or hardcoat acrylic lens for slightly more output (stock lens is about 92% efficient, 95% for hardcoat acrylic, 99% for UCL), but it wouldn't really be worth it as the the lumen gain wouldn't be that noticeable at that level. If you are comfortable with DIY work and soldering you can put a SST-50 or 90 (my mag mod seen here) in there for some serious output.

Feel free to search the forums as there is a wealth of information here.

Thanks for all the advice Kevin. It is greatly appreciated.