89 420 sel cylinder head rebuild

[dtrain]

205k

planning to have my cylinder heads rebuilt: 6, 7 and 8 are all leaking some oil

some questions:

1. Buy rebuilt or have mine rebuilt? Any suggestions for machine shops in Ohio?

2. I know how to check the rocker arms but have read that they should be replaced at this point with the mileage - thoughts?

3. Should I replace the ball studs as well and/or is there a check to determine if they need to be replaced?

4. Read how to check the cylinder head bolts for stretch. Am considering replacing all of them - a little expensive... Read a suggestion to order the bolts from a website like "boltdepot.com" - should these come from the dealership or can they be purchased elsewhere without concern?

I have all the gaskets, guides, timing chain, tensioner, etc. (will remove the front cover as well), vacuum lines (once the intake is removed) - any other thoughts would be appreciated.

thanks