Evening/morning etc..

I'm looking for a bit of experience and advice here, as usual...I've recently transplanted a very healthy
b20 with a big valve (44mm inlet) head, K cam,onto my amazon. .30 overbore. It's got a pair of hs6's and 123 ignition.
I am having trouble with the mixture/needles...if I dial in the mixture it wants at idle, firstly the jets are almost at the bridges (barely a flat away), but worse than that is the fact I get a terrible stumble, almost stall when pulling away. The car also drives awfully, exhibiting all lean symptoms. I can get rid of that by enriching the mixture a couple/three flats on each carb, car goes like stink,but then it does not idle so well at all. The carbs are sweet, no leaks, all new floats, gaskets, needles, jets. I have got kn needles in the carbs...is it possible to ascertain what one flat on the carb equates to in relation to a chart such as this great SU one:http://www.mintylamb.co.uk/suneedle/..
Because if so I could have a good guess at better needles...looking at the comparison between KN and KD, the KD is a fair bit richer just off idle, and most everwhere else. BBE looks good also. I have got 20w oil in the dashpots.I don't have a rolling road anywhere near me, least not one where they understand and can tune su's effectively. Wish I did.

Thanks a lot for reading at least.

Dave