Hi Paradox,
As you have the washer there to protect the chassis I'd just go straight for the grinder.
Now as far as reassembly is concerned you'll have to purchase absolutely identical thickness bolts. You should have no free play when the bolts are inserted losely. This ensures that the sole plate is sitting in exactly the correct position when tightened up.
Also one point to note and that is that all the four bolts should be pointing towards the left hand side of the machine (chain case side) that way the threads are protected from abrasion, so the bolt heads should be on the outside of the frame with the nuts on the inside and on the LH side of the machine the bolts should be pushed through from the sole plate with the nuts being done up inside the chain case.
Hope this makes sense to you, if not don't hesitate to ask and I'll re-clarify.
Cheers,
BB
