Not really, cause 3x 18650s are only 12v for a very short period of time then the bulb gets very under driven.
There are actually better 2D options.
The WA1274 and the FM G4 Axial 6.6v.
They both work well with 2x 26650 IMR cells with some sort of FET switch mod.
They run at their operation sweet spot with those batteries and aren't over driven. Probably not quite as hot as a ROP Hi 54.
The Axial 6.6v seems identical to the ROP Hi 53 (7.4v version) in its output and performance, but can be driven harder.
Some cheap 12v bulbs actually run better being pushed by 4x IMR cells in a 4D mag.
Back in the good old days, in a 2D mag you could run a WA1111 with 2x Lions cells and it would kick.
Today, the ROP Hi your running now probably is the best option for output in a 2D. YOu can improve it if you have the crafting skills to build a FET Switch. This will lower switch resistance, allowing more current to make it to the bulb, and with increase output my at least 10%. YOu have to be careful as with a FET switch you can almost flash a 54 bulb. Should flash for sure with IMR cells and a FET switch.
If you really want to take the incan mag to the next level, the absolute best option in my opinion is to build a JM-PHD-D1 regulated 3D or 4D.
Then you can put in a bulb rated one cell less than what you have and push it to it's limit.
The FM 6.6v Axial will out do a ROP pushed to like 8v with the JM and 3x IMR.
If you could find a good old WA1185 you can push it safely beyond what people were doing back in it's hayday with the JM and 4x IMR.
Oh and, unless you haven't noticed my hints already, 26650 IMR cells really are the way to go to get the best out of incan bulbs.
18650's with have to low capacity in the IMR/High Outputs, or to much voltage sag in the standard High Cap and their voltage drops quickly.
You may gain improvements from your ROP just from switching over to 26650 cells.
Just shooting out some opinions and ideas. Hope it helps.
