It's nice you were willing to go to that effort and expense for your family, I hope they appreciate it. But it isn't necessary to go that far if it means throwing the tapes away because it is too expensive.
I never bothered to do it, but the audio/video sync can be addressed with a video editor. The point was to capture the information on disk and toss the tape. Anyone can sync it, cut it into clips, etc., later as there would no longer be any urgency. Many TVs also cut off the edges of the signal, and nobody notices. I've even seen many movies on TV with the edges cut off, such as everything above the eyebrows. No, I don't think it was filmed that way :-)
I never bothered to do it, but the audio/video sync can be addressed with a video editor. The point was to capture the information on disk and toss the tape. Anyone can sync it, cut it into clips, etc., later as there would no longer be any urgency. Many TVs also cut off the edges of the signal, and nobody notices. I've even seen many movies on TV with the edges cut off, such as everything above the eyebrows. No, I don't think it was filmed that way :-)