7 blade 17” fixed fan vs 6 blade 18” clutch fan

Thanks for the input Wayne. I am in the same position. I have both fans, and was going to run the fixed. Can you tell me how close to the rad the center of the fan should be? I have a thick spacer and can make it any size that I want.
I have the same fan on my 340 Swinger, 383 Bee and Hemi HP2. I'll measure distances for you tomorrow. They all run basically on the thermostat.