if your old playfield is destroyed (and can be further) you lay it on top of the new playfield and drill through the old holes to place them in the new playfield. The you separate them and drill through the dimple locations with a smaller bit. Place them back together and tap a nail through the dimple holes (or drill small pilot holes).

The dead simplest way to do it is ship it to Ron Kruzman (if he does this title) and have him do it for you.

I did a PF swap with a non-dimpled/drilled earthshaker PF. Just clamped them together and drilled through the old one into the new one for the top side stuff. Didn't bother with dimples for the bottom - just put the mechs where they belong.

Maybe use tracing paper and take a rubbing of the old playfield, then overlay it on the new one for drilling.

Strongly, STRONGLY recommend reaching out to kruzman to see if he has the template for Earthshaker. You only get one chance to do that right. If he has it, you can ship it to him for drilling; he has templates for a ton of games. Might take him a bit to get to it, but if you're not asking him to re-clear it, it isnt a super long job. It WILL be a frustrating, long job for you if you don't have the setup though.

clamping the playfields together is definitely a good idea in a pinch

Clamp playfields together to get topside holes transferred.

Back dimples are mostly unimportant, so only worry about dimples for the mechs that matter, like slingshots and the like.

If you have the Mylar screen protector that came off of a new LCD TV, that makes the perfect template if you poke the holes through with a scratch awl.

Before you depopulate the old playfield, remember to trace all the mech locations with a sharp pencil. This saves mega time getting the orientations correct on the new one.

contact ron he can dimple many titles
http://www.rockcustompinball.com/ron-kruzman-playfields

Smart move.