Hello a newbie trying to fix a mess - rocker stands

[Uglydog56]

Hello - I'm another newbie. New to Mercedes, not new to cars. I'm looking for information to fix my ex-wife's boyfriend's car - long story. It is an 87 260e with only 121,000 on it. The top end was hammering real bad, it was missing terribly, and two cylinders read low but not the same every time on the compression test. Took the valve cover off and (some of you probably see where this is going) 4 of the 6 rocker stands were completely loose!

I haven't lost any of the lash cap thingy's. But I'm going to have to helicoil probably 5 of the 6 rocker stands. Is this ok? I'm probably going to do all 6 just so I don't have to go back in. Cam looks okay. Rockers look okay. Is there a max depth to drill for the helicoil? And lastly, what is the torque spec on the bolts? Thanks for your time.