I don't think anyone in Rajkot or India is casting SOM flywheels.
I would study the oversized hole problem carefully. How true is it? Steel or brass shim stock of any thickness is available, if you can get a decent fit with a hand cut and fitted sleeve, I'd think about Weldbonding the sleeve in the wheel. I'd do the fitting first with a piece of 2" shaft- I got one pretty cheap on Amazon and use it for flywheel balancing per 38ac's method. Check flywheel runout on the crankshaft with the shim stock before Weldbonding it to the wheel alone. Likewise I would think about brazing the hole, and hand fitting and rebrazing to get rid of runout, both lateral and vertical.
Lots of work and way easier to grab a replacement if available.
Best Wishes,
Bruce