Do you think this would be a good match for my Collie?

I have a Rough Collie that is 10 months old. She weighs 55 pounds and is 21″ tall and 28″ long. We want to get her a dog sibling. We are considering a smaller dog, our first choice is a Cavalier King Charles Spaniel that would get to be about 12″ tall and 15 pounds. In your experience is is a good idea to get a 2nd dog that is so much smaller than the 1st. We will get our 2nd dog as a puppy not an adult.
Thanks for your insights.
Soda, our Collie, is a very fun-loving dog and just LOVES other dogs:)

Is a Rough Collie the dog for me?

I’m looking for an attractive dog who is smart, friendly and loyal. I’m 15 and will be training the dog myself and will be its master. I’m living in a warm area that can be quite humid but I also live close to the beach and will be taking the dog for daily walks. I have a big backyard as well.

I have fallen in love with the rough collie and am willing to groom it as much as it needs.
Can rough collies live in warm and sometimes humid climates?
Since its my dog I’d like to train it but my dad has more authority so would it be better for him to be its master?

Also is the collie a good beginners dog?
I mean my family has had dogs before but I’ve never been the one to control/train it.

If you have any other facts on this breed it would help immensely!!
thanks x
I dont really consider myself as a ‘master’, it’s just the only way I could think to describe it at the time :)) I believe more in getting a dog to respect me so it will listen to me instead of actually ‘mastering’ it x
Also I have thought about the future, there is a uni that my entire family has gone to nearby and a granny flat attached to the property and I am planning on living there through uni, I’d never buy a dog if I if I thought I wouldn’t be able to keep it in the next 3 years. And the dog will be kept indoors and only outside when we are there to play with it. It will essentially be my baby/best friend haha

Is there a dog breed that looks like the border collie but is a little less active?

I am in search of a dog. The border collie has the right size and right look.
But i need a dog that is a little less active but a good running partner. Any suggestions?
let me rephrase this, the all around temperament of this dog is great except the activity level i cant give the dog a daily job to do.