Somebody has probably already done this. I recently tapped a 24n-117 Senator handle $41.25 for the 110-50 screw to accept the 110A-50 handle lock plate for a 116A. Tap 5-40 NC $3.88, lock plate $3.45, and screw $0.07. I didn't use the correct drill size #38. I used 7/64 bit I already had . No problem it tapped out nice. The 5-40 holes are spaced far enough apart (1/4") from both edges. The lock plate hides the old screw hole. Use the handle lock plate as your template and a spring loaded center punch to mark your hole. The 24n-80 International handle would work, for about twice the price. I brought a Senator from a member here that already had 24n-80 on it. It looks awesome with it on it. After looking into handle and arm costs ($$$) I did this instead. The original handle is put away. I just finished a second one on the 14/0. Jaws stays like it is and in the box. It's little brothers now have lock plates.
Well done! I have had reels that have had this mod done accross my bench before. Also, the other way around (i.e. use a new rubberized senator handle on an older international 80.
Thanks for sharing.
Looks great!