Fuel / Air mix adjustment

[Bombasstic]

I have stripped, cleaned and adjusted floats etc on my GL 1100 carb (hunting for a cause of my #4 cylinder running rich and plug fouling up)
On putting the carb back in my bike I did a test of pulling the plug wires to hear the changes. I found pilling #1 and #2 has a major effect of almost stalling the motor . . . while on the other hand #3 and #4 has almost no effect at all (#4 a bit less than #3) With #4 pulled, I could in fact go riding on my 3 cylinder Gold Wing. . . . very strange. Is it normal for #1 and #2 to be "dominant" ?
I know this is at idle and the Fuel / Air mix screw is in play but could they cause such a massive difference ?
I set all 4 screws at 2 turns out before installation and have left them there because I find it impossible to set them once the carb is installed.
I live out in the sticks and have no one to borrow the adjusting tool from.

If anyone has got advice re the #4 cylinder running rich I would appreciate it. As far as I know, the float height is the only adjustment that can be made ??? I have checked all wiring and coils etc. and find no fault and the spark is good. . . . .

Feel free to offer your 2 cents. Thanks