I'm playing about with home made igns and have read all the info etc on here, there is a lot about the ign controllers but very little about coils. So from what I get so far:

Kettering needs about 200 turns primary, 20000 secondary, (100:1 ratio) draws about 1.5 amps on the low volt side and will work on 4.8 or 6v

CDI needs a lot less as its already at 2-300v primary, so 40 turns primary and 2000 secondary (50:1 ratio) is okay for 4.8v

BUT, it sems a lot of people just buy them from CH rather than make them, but I'm in the UK and there is no supplier for small ign coils here. I'm currently using a 6v motorbike coil but its a bit heavy. So, has anyone made a neat smallish coil and if so what turns, core shape/layout and wire gauge did you use, and what input voltage? I guess there are a few more out there who could use this info as it seems there are quite a few home ign builders.

Cheers in advance,
Rich