Grand idea if you're doing 10 to 15 years in prison and have all the time in the world or, for $7 - $19 per tape, you can bring it to me and have, say 20 tapes, done in one day. All this struggle and strife won't get you any better results no matter how much FCP wizardry you throw at it*.
Here's the reality of things. You're dealing with VHS tape (240 lines resolution) or Hi8 tapes (400 lines) which is paltry what's displayed on todays equipment. These look fine on old CRT devices because that's what they were played on. There's no amount of magic, even capturing in ProRes 442, that's going to make them marginally better so capturing at 13GB/hr SD file size isn't worth the effort cobbling this nonsense together. Run one standard VHS tape of 2 hours length and, congratulations, you've worked for $10.00 per hour. Spend another two hours futzing with the edit and rendering out then you're at slave labor rates.
*The only exception to this is on film transfers. I roll those in 1080HD ProRes 442 and have 18 drives to capture the 1.1gb per minute file size. This is a sample of a clients previous tape transfer running the original film as described. You'd NEVER see the threads on the sleeve or the second hand of the watch of 8mm film captured to tape.