The second design on the drawing board was the parabolic reflector. All the light for this cone is reflected to the point right in the middle and in line with the top of the cone so it should be easy enough to find the hot spot. The calculator for this can be found here. I started to scale this one up to 1m in height to create a very large reflector until I was reminded that I'm going away next weekend and I haven't sorted out my costume (non laser cut) for that yet so I had to switch projects mid day. I will be returning to this subject though.
Also this is item 160 in 160 days, I should enjoy it while it lasts though because I'm away for 5 days at Easter and we're due to move house any day now.