I think the biggest challenge is obtaining quality, calibrated equipment. This particular set uses a separate IF for sound/video and stagger tuned video IF. You don't actually use a sweep generator for the alignment procedure. Rather you need an accurate RF gen. with good output attenuation. Also quality, terminated test leads are a good idea.
The sweep gen and markers are just to check you work. If the overall pattern is off, you need to go back through the fixed frequency tuning steps. I did about 4 passes to get it right.
I didn't touch any caps in the video IF, but I did replace some exposed micas in the sound IF cans. The biggest surprise was the effect swapping the 6J6 osc/mixer tube had.
The original was a little weak so I popped in a NOS one that tested great. However, this is the best response curve I could get.
I was considering popping the tuner open to check for bad components when I tried swapping in another NOS 6J6. That did the trick
I later read in the service info that indeed an RF alignment may be necessary after replacing the 6J6!
I do have an RCA WR-514 which like the 415 uses crystal controlled markers for 44 MHZ IFs, but all my sets are too old to use it.