Would offset grinding a cast 440 crank significantly weaken the journals?
2.375" down to 2.200" and adjusting the stroke from 3.75" to 3.91" would reduce the journal overlap by about 25%


or would the chamfered edge and lower rod weight and smaller bearing surface counter the loss of material?
Have you spoken with your crankshaft grinder to see if it's possible? Without welding, you'll take 0.020-0.030" or more to get below the undercut, before you can even start start producing a fillet. Start taking off too much and you move the position of the oil holes on the journal.