VHS to DVD over 3 hours per tape?

If someone put more than 2 hours on a VHS tape quality probably wasn't their biggest concern.

Putting more than 2 hours of video on a DVD-5 will only result in quality loss but you could get it on a dual-layer disc.

Some players are picky about how well they will consistently play DL DVD-+R media. Unless the computer drive is recent a lot of drives can have issues with DL media.

You could also author and build the DVD non-DL in DSP and have Toast compress it to fit on the DVD-5.

I would consider buying a DVD-R recorder. It will save you a ton of compression time and many potential headaches. Medium quality ones aren't that expensive.