Set off a gallon of elderflower wine and a gallon of rose petal wine. Both should come out around 8%.
The yeast is old, so not sure it will work but hey a bit of foraging with the dog in order to collect means its not wasted.
I'm sure the yeast will be OK.
There are a lot of elderflowers around at the moment. I might have another go at Elderflower wine or Elderflower pale ale.