Now that can be a tough question, as you said all chins are different.
As a general rule I would have to agree with Jamie, and she's bought way more chins than I ever will.
But with in my own experiences it's not so cut and dry.
I got a pair from a fur farm at the age of 5, plus their 1 year old daughter. They were never spoken to let alone have names. Though they were never with out the basics necessities of life, but they never had much more. They were the sweetest calmest, most handle able chins I had seen up to that point. So Why?
I also took on a five year old male that was very well taken care of and had everything a pet chinchilla could dream of. He was just as calm and handle able. Why?
I've shipped in chins and some seem to have changed from the stress of the trip while most, seem totally unaffected.
Their breeders kept me posted on their temperaments.
Most my kits I find love being held right from birth. They love the warmth of you hands, and will sleep balled up for hours. As they age and get spunkier most will stay people friendly, but some just realize freedom and will do everything just to get on the floor. These are squirming for play and not fear.
It helps to learn the difference in all chins, cause they can be tricksters and very adamant when they want something. So knowing if they are squirming for fear or control makes a difference on how you'd handle the situation.
It all takes time, and I haven't had one yet that I couldn't get a good bond with. You just need to learn what makes each happiest and use it.
If you are looking for a calm, well behaved pet I'd adopt an older animal that has had a good slave in the past.
Kits are just like puppies, you never truly know how they will turn out. The first year requires a lot of training & patients,. Their energy levels and curiosities seem to be at it's peek during that first year too. As the age they do calm and given a good routine will be quite accepting of human interaction.
Being able to handle any chinchilla before you purchase is a must. If it's totally uncontrollable I wouldn't buy it unless you were up for the challenge.
I show all my customers the correct way to secure their chin with the tail hold. I watch them with the chin so I can give them pointers on how they are holding it and try to get them in a couple fo times. I can't imagine having them come take a carrier with a chin in saying good luck!
Most of us with multiples really don't care, we love all the different personalities, are not in a rush, and are willing to take what ever we get personality wise.
Most any chinchilla can be conditioned to tolerate handling, scratching, and a scattered cuddle with out any stress.
As Jamie says it’s all about patients… and routine.
As hard and as sad it is to leave the chin in the pet store, keep in mine as soon as he's sold another will be placed in the plexie glas cage.