Rear Monoball mounts are now completed with a plate to adapt Ohlins R/T coilovers for installation with the monoball mounts.  As seen in the pictures below, the Ohlins set comes with a mold formed rubber insert that fits into the OEM strut mount and locates on the three OEM strut mount stud heads.  A machined aluminum part then fits into the bottom side of the rubber insert in the Ohlins kit.  The machined part has a lip with an OD that mates with the spring. 
The Ohlins rubber piece is so large and has such a radius that making a monoball mount that would still fit properly in the car body and have sufficient wall thickness was not possible so I designed and built a different aluminum insert that would locate on the stud heads, be flush with the bottom plate of the monoball mount, and have the correct lip/OD to mate with the Ohlins springs. 
 
 
A rubber washer supplied by Ohlins sits between the aluminum lip and the spring.  Inside the cup is a FK Com14t F1 fit spherical bearing captured by a cap with 5 M5 screws.  Bearing retainer compound will be used for the bearing locating surfaces with Loctite blue on all screws/nuts.
Here you can see the monoball, adapter plate, and spring from the side view.
 
Here is the assembled monoball and coilover though I need to increase spring pre-load by 5mm.  I couldn’t tighten the pre-load spanner nut any more by myself. Aluminum will be anodized blue.
 
I am done with machining other than building drop link adjustment centers after getting everything installed and measuring what length centers I need to build for front and rears.  If all goes ok I hope to get the car on the ground again this week.  The only issue with this is I can’t get tires I want and the ones I had are completely done.  Stupid Covid shortages of everything…