OT61: you have made a god start! Before you inlet for the entry pipe and the trigger and plate, determine where your ramrod hole lays within the forestock. To do this, drill a small hole in the barrel channel near the breech end of the barrel, and into the rod hole. Now insert a small wire until it bottoms, and measure its length. Mark this length on the lock side of the stock adjacent the hole you've drilled, and that'll show you where the hole's bottom is. If you have wood, start cutting it away reducing the height of your stock through the lock area. It looks to me that you could cut away 3/16" at least along the bottom of the stock, if your rod hole will allow it.
Don't outline the lock panel with a rat tailed file! Instead, file the wood off away from the lock panel toward the centre of the bottom of the stock. Leave an area flat about 1/2" wide so you can inlet the trigger plate, and then finish cutting away the bottom on this same angle right up to the plate inlet. Your lock panel should be only about 1/8" wide around the lock, especially along the bottom edge. Duplicate the lock panel on the off side, and try to cut away those concave moulding lines.
Once you have the trigger, plate and guard inlet, you can further round the grip and forestock to get away from the slab-sided look. A pistol of this design can be delicate like a bird.
