Sorry I could not resist.
You already get enough tannins and nutrients from the raisins, that's what they are there for. I think you are in the danger zone of mixing very old recipes with newer science.
Case in point, Sir Digby said to mix the must until an egg floated 1/4'th above the surface. Thank you but I'll use a hydrometer and not put a nasty egg into my expensive must.
I would buy another fermenter, cut this batch in half and mix it with another batch of mead already in full fermentation with a healthy yeast starter. ( two packets of dry yeast going nuts for at least two days ).
From there, it depends on "ho" (how) it taste to you. (Sorry, I grew up in Hawaii and uncle Don always made "phun" of his name).
Best of luck, and welcome.
In Primary: Belgium Chimay clones.
In Secondary: Braggot, pale ale, end of the world white.
Conditioning: Mead, Cider, braggot, Belgium Wheat.
On Tap: Clones, Chimay Blue, Red, Porter, malted cider.
Bottles: Far, far, too many to list.