adding grape tannin to mead

[SagamoreAle]

How much tannin are people adding to their meads? I've been adding 1/2 tsp to 5 gallons and am thinking about increasing. I'm looking to add a little more complexity without too much astringency. What is the collective minf doing?

 

[chickabeelane]

What about oak? It will add complexity without astringency.