I would leave the inletting of both channels alone and make the following mods.
First, I would install the nosecap, or at least draw it on the wood for reference.
Lower the ramrod channel to the indicated point determined by having at least 2/3rds of the thimbles exposed.
Place a thick pencil alongside the barrel flats and draw a line on each side from the muzzle to the side panels.
Draw a line indicated by the left and right apexes of the red lines. It will run from the nose to the forward edge of the lock moldings. It will establish the highest point on each side of your forestock. It will also determine the line at your entry thimble where it transitions from the tang into the forestock.
Remove wood as indicated, but leave the pencil lines...centerline to barrel line, and centerline to edge of ramrod channel. Once that is done, sand the sharp edges and round them to your original profile in a gradual ellipse.
This is my "in progress" Figthorn, Reedy, Bonewitz.