
This happened to one of my girls. I was more than happy with using Alizin. Don't think I would have gone for the old style jabs. Like you, these were 24 hours apart. I didn't wait until the end of the season, as I was very certain that I was going to crate in seperate areas of the house afterwards.
I'm not sure what side affects you mean, but if your vet is using Alizin, I would definitely recommend it. And I wouldn't have your bitch spayed yet if she was mine. I like my girls to mature and develop properly first.
This was the first time I have used Alizin, and the girl who did the jabs told me that she had never known any problems with it when used early enough. I had my bitch done 24 hours after the mating, and again 24 hours later. Go for it. Honestly. :-)