Alan, if I would be at your place, I would have moved to a program like link detox instead of the manual labor and here are some reasons why!
- You are emailing to the real people so no matter what trick you use, there are chances that you may fail, especially if they have decided not to remove the links.
- The removal ratio can dramatically increase if you offer a small amount to remove a link but again disavow is a better and easy option that will help you save your time and money.
- Manual Labor to do a work that might or might not work is a bad investment in my opinion, on the other hand manual labor will be much more expensive as compare to a tool like Link Detox.
Link Detox will find bad links, email them and give you the list of bad links that contain your website link. You can get that data and create a disavow file and submit it to Google.
All in all, I understand your point but in my opinion it is not a very good investment.
Hope this helps!