Here's a few pics of my first aspheric head. It's a outputs a very bright spot so I guess it's doing what it's supposed to on that front.
I used the following parts:
Driver: 9A Buck Driver
Lens: DX 28mm aspheric
Housing: delrin, alloy, acrylic (6mm)
I played with a few different aspheric lenses from DX up to the 66mm one, though the 28mm was the best size and from my visual tests output the best light.
I also gathered along the way that the smaller sst-50 might have been a better choice, but I'd already ordered the SST-90 by that stage. I'd be curious as to whether the SST-50 would