Jason

I agree with the previous posters.
Here is how I would procede.

I would have JJ make a new splinter fore-end using the original fore-end "iron". Thus saving the original fore-end wood.

I would see how the rifle handled with the new "front wood". If it was still to bbl heavy for me I would add weight to the butt stock.[ I would put a Murray Leather buttstock shell carrier on it, 6 rounds of 500 Nitro ammo should make it balance perfect.]

I would NEVER, EVER, cut down the barrels.

My favorite double rifle is a 450 No2 with 28 inch bbls.

I have used it in the THICK, THICK, THICK, Jess, for elephant and buff without problem.

Big Bore Doubles with 24 inch bbls feel to stubby to me.