1) I don't feed raisins. They have too much sugar, and grapes have been found to be toxic in several species, so I just avoid it for better, safer treats. Bite sized shredded wheat (non-sugared), the occasional cheerio, dried rosehips, and chin safe wood chews, which are a treat and work to keep their teeth worn down.
2) Do you WANT a cage that is taller than 5 feet 6 inches? Or are you looking for one that is less? The only cages I know that are that tall are of the super pet type (wide wire spacing, plastic bottoms) and those are fine, but not for babies and pregnant moms.
3) It's my opinion that you don't just have a violet producing pair. You need many animals in order to produce a quality chinchilla when breeding mutations, especially violets, and they all need to start with your standards. It's going to be the same with whites. To get good quality whites, you need a good quality standard to put them with.
4) You don't even own a chin yet - so you are unfamliar with it's care, it's housing requirements, even genetics. You need to do a lot of reading before you jump into breeding. Start reading through all the FAQ's in the chin breeding and baby section. Actually, it would be a good idea to read through ALL the FAQ's about chins before you buy, and definitely before you breed.
A few questions:
What is the gestation of chinchillas?
What is the lethal factor?
What is a "carrier", as in, violet carrier, sapphire carrier, eb carrier?
What is the average litter size for kits?
What is the weight considered safe for breeding for mom?
Where do you purchase chins for breeding?
What is a pedigree?
What do you do if mom can't support the kits?
What is considered a "baby safe" cage?
What is malocclusion and how is it passed on?
Do you have an emergency vet and at least $500.00 in the bank in case the need for a C-section arises?
Those are just a few of the questions you should have answers to before breeding, and it really wouldn't hurt to own a chin before you start making plans for breeding. There is a lot to learn. We're glad to help you, but you'll really find a lot on your own by reading those FAQ's.