Here's my rule:
If it has a red icon, and if it's within my means, it dies. No exceptions. I've had similar situations, one recently with a Mustang. I simply spiralled down in my Yak, and the instant he recovered; whamo. I don't expect less from the opposition. I recently managed to spin an La-5 while fighting with a Spitfire. He tried to kill me while I wrestled with the La. He missed and it cost him a little later. However, I had no problem with his trying. But, as Westy pointed out, hitting a spinning fighter isn't easy. Best to position one's self to nail him on recovery (that is if he does recover), assuming he has no friends around to spoil your chance.
I've had enough experience with uncharitable pilots to realize that it is far wiser to shoot first.
My regards,
Widewing