4-6 drop and wheels

[2500HD]

My 4-6 drop and disc brake kit from ECE will be here tomorrow. I will be installing on a 67 short bed and my axles are being redrilled and the flange is being turned down.

My wheels are Eagle 211 (torque thrust look a likes). The front are 20x8 with 4.5 backspace and 255/40/20 Toyos. The rears are 20x10 with 5.5 backspace -- I plan to use a 1.25 inch spacer because 5.5 is to much backspace. The rear tires are 295/40/20 and my final backspace will be 4.25.

I am 90% sure 4.5 is the correct backspace for the rear but Eagle only made the 211 20x10 with 5.5 and without cutting down the wheel studs the spacers need to be 1.25. The end result will be 4.25 backspace. the question is are the tires going to rub? Keep in mind I am using the narrower rear end.