FWIW, I did this again on my "new-to-me" car - a mint condition 2006 Mercury Grand Marquis LS with a 4R75E.
Some people mentioned that the 4R75W and 4R75E have much of the J-mod completed by the factory with larger holes in the seperate plate. I found this to be untrue.
Every hole that was to be increased in size was smaller than the required drill bit. One was very close, but slightly smaller than the drill bit.
On this car, being in such great condition, I opted to swap the 1-2 accumulator springs instead of remove the lower 1-2 spring. I removed the original green and inserted a softer light-blue upper 1-2 spring and removed the two lower springs and replaced them with a single purple spring. This resulted in far better than stock shifts, but not as firm of a 1-2 shift as my old 2000 Grand Marquis with no lower 1-2 spring.