Idle bypass air is a key element in tuning idle without transfer slot exposure. An easy way to check you bypass air is to pull a vacuum accessory like power brake port and cover it with tape. Poke a 1/16 hole in the tape and close the throttle blades a bit. AFR cleans up. repeat with 3/32 and increase with 1/8 all the while dropping throttle blade angle until you achieve best afr and idle. Check your corrected vacuum and install correct power valve. One you have the diameter of idle bypass figured out you'll know how big of an orifice must be drilled into the throttle blades, or you may open the secondary blades slightly with the set screw in the base plat mounting flange.