the rods are turned to a standard size, and you chose the inserts that match the undersize you are grinding the crank to, just like modern engines. You are probably ok grinding the crank to .010 under specs and just getting .010 under inserts (thats why the call them "precision" inserts. Just make sure to give the shop the exact specs you want it ground to, as the mains are all different sizes, and most of the machine shops look at you like foghorn leghorns nephew when it comes to these engines. Also be sure to check the clearance upon assembly just like any other engine.
