Several people have tried to explain to you that the front and rear idle mixture screws have to be set the same. 3/8 to 1/2 turn out from seated is typical. Do not try to set the front carb for best idle first. When you do that it is trying to feed idle fuel to all 8 cylinders from one carb which is why you wound up at 1.25 on it and then the rear wanted nothing. You have to adjust both carbs at the same time. I know it is a pain but when you think about it it makes perfect sense. Again, 3/8 to 1/2 turn out from seated on both carbs is typical not 1.25. Forget about the finger over the bleed trick. It is BS that was first printed in the early to mid 70's and repeated a 1000 times since then. Please forget you ever saw it.

You never said what your initial and total timing is. This is critical. If you don't have enough timing at idle then you will wind up with the idle speed screw adjusted in too far. That will expose too much transfer slot and then the center carb will feed too much fuel and you will probably try to correct it at the mixture screws. You will be chasing your tail. You need 18 deg or more at idle before you ever start trying to set anything in the carbs. You will probably need to recurve the distributer to maintain the correct total timing.