I had an Ultegra double FD on my 46/33/22 touring bike and had no clearance issues. Tiagra FDs are standard on most touring bikes with STI shifters, so the high zoot stuff is not necessary unless you want it.

I would be worried about stress cracks from a hole drilled into the frame, and it seems like an extreme measure when a used Tiagra FD can be had for less than $10.