We PM'd but in case there's other interest I'll copy some here...
I made two rosehip wines using wild roses from the property, rosa canina, the dog rose. The first one I left the seeds and OMG is it bitter. There might be flavor hidden somewhere but the bitterness was overpowering. I think my reaction was something like "Holy Shit!" It's still in bulk. Maybe
someday it will be drinkable.
Because of that experience I
had to do another. Got rid of the seeds and it was COMPLETELY different. Delicious! My first thought was that it tastes like a cherry wine! Seriously! I was surprised and happy!
So removing the seeds might be a good idea.
I didn't add tannin to the one with seeds. Wasn't sure about the 2nd so I only added 1/8 tsp. I might add a little more next time.
I didn't add raisins to either. Next time? Maybe a bit. It's a coin toss thing since I was happy without.
Adding apple juice is up to you. From my happy experience with the 2nd one I wouldn't. The first time I use a new ingredient I try to keep it as simple as possible just so I can experience
that ingredient. And I don't think the rosehip needs any help. But that's me. Everyone's style and taste buds are different, of course, and you're the boss.
I have to add I'm surprised rosehips aren't used more for wine making. Delicious!