No need to use so much Tufoil in your engine.
Tufoil needs a carrier oil, that is your engine oil.
Tufoil is a friction reducer while modern engine oils have other properties that are also needed for your engine. Anti-sludge, dispersants, detergents etc. They are all very important to your engine.
For our own cars, we have been using Tufoil for years already. In our case, it has been 1 bottle throughout and progressively we find the engine quieter and more refined.