Before I would modify a reel foot, I would cast the rod to see if you even like it. Many old bamboo rods were really not great casting tools.

So take several reels with the some fly lines that might be the right weight and try the lines. There is no need to actually put the reel on the rod. You can put the reel on the grass and string up the rod and cast with the line. Or you can tape the reel to the rod with masking tape.

When and if you find the reel and line that matches the rod, you can modify the reel foot.