Going through a similar exercise. I just put a Williams WGRS and a Williams .445 front sight on my Black Diamond XR. I am planning to put a NECG N-106 on a newly acquired Knight LRH. Not sure if I will need to put on a different front sight to match up with the N-106, I will just have to shoot it and see. I was told by williams that the combo on the Black Diamond should work but I will need to shoot it to verify as well. The Williams FP sight looks awesome but I could not figure out how to mount it on the Knight and I dont think they make one for the Black Diamond.
I am sure folks a lot more skilled than me will be along shortly to give you more options. Williams and NECG were really the only two options as I have not yet warmed up to the globe sights.