Does anyone know how thick the reaction disk in a 71 240 should be?

I pulled out the push rod and the disk fell down into the power booster. Instead of taking the boster out and fishing around for the disk, I thought I would just replace it. I have some 1" rubber washers that I am using. The washers are about 1/16th each and I am stacking them where the reaction disk goes until I get the proper thickness. The haynes manual drawing does not seem to be to scale.

71 240z

I just spent about 2 minutes with my fingers in the booster fishing for the rubber disk. Caught it. Have the booster on a vise drying the paint before I install it. Went down pulled the disk and checked the thickness, on a regular measuring tape it is 3/16 thick. Covers both lines on each end. You should try fishing for it. I have been driving my Z for 5 years now with the disk lost in the booster. Talking about safe driving. Hope this helps.