Need help choosing an Led

I want to mod a light my father's bday in august but I am having a hard time choosing an led.

My choices

1. sst-50 or sst-90. I want to drive either of the two @ 5 amps. Which led would be brighter @ 5 amps? Which one would run cooler? Also what choices do I have for drivers?

2. 5*Cree R2 1200-Lumen White Light Drop-in LED Modules sku 35241 from dx

I know I would have to mod the mag a bit for the drop-in. Also know heat-sinking this bad boy maybe a problem.

Richard

I have been doing a bit of research. Seems there isnt a whole lot of drivers available. Alot of dd mods. I have some extra NIMH d cell batteries so I want to use these for this mod.

If you decide to go with the ssr50 then I would recommend the c mag. If you were going with the ssr90 I would go with the d mag. It appears that you have more color options with the d mag and you can get better heatsinking. You can direct drive a ssr 50 and ssr 90 with either a 26650. Be careful with the ssr50 though as I have read that some get over 5 amp with the 26650. It is difficult to drive a ssr90 at its max on the c mag because of the heat. For heatsinking I would go with the britelumens heatsink. But I think there are other good options on this site as well for heatsinking if you just ask around. I made a 2 c mag with a sst90 and managed to poof the led and I kind of wished I went with the sst50. Check out aircraft800 mod with the sst50. Good luck with the build

Besides britelumens, who else sells a heatsink for the sst-90. I have searched and searched but no luck. Probably a stupid question but I'll ask it any way. Would I have longer runtime using a D cell batter vs a C cell?