Cap Studs
If your cap bolt threads are stripped, or in danger of becoming so, all is not lost. The head can be restored by installing M6 x 1.0 3D helicoils. These are 18 mm long.
You'll need to drill out the existing thread with a 6.20 mm drill to the full 22 mm depth for the 12 cam cap holes.
When installing the helicoil, apply a light coating of Loctite 262 to the outside of the coil. Once installed, let it set for 3 hours at 22C before washing with isopropyl alcohol to remove any residual Loctite.
The helicoil should be at least a quarter turn below the top of the hole. To be sure, mark the start of the thread before installing the coil and finish a quarter turn beyond it. If you are paranoid, positively lock the coil in place by peening the aluminium thread over to capture the top of the coil using a fine punch. (I didn't)
The cap studs should be 49.5 mm long and at least R8.8. R10.9 is better, but much more expensive, R10.9 rod should NOT be plated due to corrosion issues. Threaded rod is fine if you can't find proper studs. Use Loctite 222 and torque to ~6 Nm by bottoming the stud. Let it cure for 3 hours at 22C.
Use Class 8 nuts, hardened washers and lubricate the threads. Torque to 10 Nm if R8.8 studs, or 13 Nm if R10.9. I tried 13 Nm on a test R8.8 bolt & nut, and both threads were marked up, so best stick to the recommended 10 Nm.

Bridge Studs
The 4 cam bridge holes are 30 mm deep.
The stud length is 66 - 67 mm.
I haven't installed studs for the bridge because I wasn't sure if there would be enough clearance to the frame to remove the bridge with the engine in place. Now, with the engine installed, I have measured the clearance from a parallel line across the top of the cap bolts to the frame as > 70 mm, and the bridge would only have to be lifted 37 mm (67-30) to remove it from the studs, so there is no cause for concern.