I just had non-click event (3rd actually) on my 1974 Mac wrench forcing a play.
I can confirm that CDI is a snap-on company. The Williams brand and CDI brands are assembled in City of Industry CA. Williams and S-O are all USA parts, CDI is world sourced. I got a CDI brand, Amazon.
The MAC T150FR has served me well. MAC would not service it, as it has a babbit plug poured into the end to prevent calibration. A clever design with little tamper traps like the temple of doom. Washers that spin to thwart drilling etc. I got it out safely, lubed and recalibrated the MAC within 1.5%. The internals were only polished not really worn. Repairing saved me $200 for a new CDI or cost $1500 in labor.
If one wants to check calibration, I used the electronic torque meter
from HF, a real deal for it's function. It looks like they are discontinuing this meter, only $20 on clearance.
The CDI is a 3/8" with 100 ft-lb max more size and range match to the -7. It will fit better in the spar box.
To the OP's question, I use a 0-80 in-lb beam, 50-200 in-lb click and now the CDI 10-100 ft-lb click. And a Fat wrench to check the 25 in-lb items on annual. A 1/4" drive digital with beep , 20-100 in-lb would be a welcome improvement and time saver for odd positions on annuals. The beam is limited in its uses due to lack of positioning and viewing.