I'm doing what you're aiming for apparently, except perhaps my tapes are in better shape than yours if you feel you need a (built-in) TBC. I'll say that, with tapes in good condition, my tests on the JVC 9911U reveal that having the TBC on lowers the image quality. This is partly because, on the 9911U anyway, the TBC switch is combined with NR (noise reduction) switch. They are the same button; I can't have one on without the other. While the NR isn't bad, the captures still look better/more detailed without it, and I'd of course rather capture more detail and do controlled NR later with (avisynth) filters. So I have it ("TBC/NR") turned off for all my captures except where the TBC has to come to the rescue.
The one feature that I do like on this VCR and use almost all the time is the "Video Stablization." You need to do a little testing to figure out the best settings combo, but once you do it gives a nice, crisp, full frame capture, no video head noise at the bottom. So I say, if you can find a JVC that doesn't have TBC/NR but does have Video Stablization you'd be in decent shape to do capturing if your tapes are in good shape. You surely know about the DataVideo TBC-1000, right?
That's my two cents anyway, for whatever it's worth. Note that I'm not a pro or anything.
