Diamond Lux III in MagLite with NiMH batteries

I've got the Diamond Lux III upgrade in my 3D MagLite. As I get my use out of flashlights, I would like to use NiMH batteries. The problem is that I want to get the brightest possible out of this and the NiMH batteries are 1.3 instead of 1.5v. So my Diamond Lux III which should be getting 4.5v is actually getting 3.9V. If I put it in a 4D MagLite I would be giving it 5.2V, if I put a 2D Diamond light in my 3D MagLite, I would be giving a Lux III designed for 3V 3.9V. How much or can I overdrive a Lux III Diamond without burning it out?

I'm using the Titanium 9000 mAh D NiMH batteries which are rated at 1.2V but put out 1.3V.

AAAHH!!!!! /ubbthreads/images/graemlins/str.gif
The diamond modules have plenty of trouble handling regular voltage as it is.
Overdriving these would be /ubbthreads/images/graemlins/mecry.gif before long.
They get hot easily at regular power, because they don't have a way to get rid of the heat they generate.

The batteries, Nimhs are usually at 1.35-1.45 when they come off the charger and can dump a lot of current through an led even at less than 4.5 volts.

Most luxeon3's are only rated at 3.7 volts, but here's the scary part.
Many are made with an even lower forward voltage rating and won't last long direct driven in a 3 cell light.

I may have read their site wrong, but the 3 watt lux III is designed only for the 3 cell MagLite. So I guess if I put it in a 4 cell MagLite with 4 NiMH running at 5.2V that would be the end of my Diamond?

I would have a heatsink made for that before I even considered it.