I measured the pulleys.
The idler pulley is 97.30mm
The AC compressor for the R134A system is 146.80.
The crank pulley is 185mm (I couldnt get my caipers in position around the fan, etc)
All measurements are the Outer edges of the pulley.
Please see my rough keyboard sketch
From the top of the (1) to the bottom of the (1)
I also put the belt on the crank and the AC pulley and marked how high it would go if I pulled on it, then I pushed the Idler pulley down and it won't even go far enough down to the Max of what the belt can stretch.