Is it ok to add undiluted Bellhammer Gold to Honda Tact AF75 gear oil? If so, what is the best rate of addition?

You can add LS Bellhammer Gold undiluted to Honda Tact AF75.
The recommended addition amount is usually 5-10% of the amount of gear oil, but the more you add up to 20%, the stronger the effect can be drawn out.
It can be added to engine oil as well.