The FH012AA is one of the better ones , still a shunt type but a very effcient one none the less. Next would be a series type unit (Only available from the U.S though), but would certainly be the best.
Yeah, sorry should have explained that bit in previous post. Whe dealing with the round white connector be careful as it has 2 other smaller wires which are from the crank sensor (I just cut out the plug and used a fully waterproof connector for them)