If your vet does not feel comfortable spaying her then I would begin looking for someone who has experience with tinnies like her. They can spay rabbits and Guinea pigs so there is no reason not to spay her due to her size. Do not leave her alone with your poodle~you just never know. Those hormones will kick and and there could be an accident. I can see that you are willing to do things the correct way but it only takes a minute for a tie that you don't want to happen. Good luck and welcome to YT.