This won't be of much help, I suppose, but I've found the best way to keep whatever quality there is on a VHS tape, is to use a dual VHS/DVD recorder and record to a DVD RW.
The recorded DVD always seems better quality than the VHS that went in (and better than direct to the PC).
I then rip the DVD to the PC and make whatever format is required.
That being said, my video capture stuff isn't exactly top-notch direct to PC. There's a bit of a dangle with the dongle
