You can check for air leaks by spraying some carb cleaner around any suspect spots and seeing if the idle changes. I doubt that blanked-off port in the manifold is a factor, but that's how you can be sure.

KD needles should be fine, but please do check when you have the time, just on the off chance that someone mismatched them.

Try to find the edge where the best idle degrades as you go richer, dropping the jets down. Set it so it bare doesn't degrade. Ideally the plugs should be tan or gray -- white electrodes is no good. It's normal for the outer edges to be black.

Please do not advance past 20 degrees at idle, even if you can go more without pinging. Do check that the advance increases to about 35-38 BTDC as you rev the motor.

I'm not sure a B18 with a D cam will idle smoothly at 800. Nothing wrong with having it idle at 1000 if that's what it takes to smooth it out.