*Thank you for the comments * ~ Glad you were finally able to view it !!
Wrigley just turned 7 months old...and our black Lab (Zeb) is 3 1/2 yrs. old.
We thought the size thing might be an issue too...but our lab is extremely gentle. I'm probably predjudice (*blush)
...but he is also very smart. He just sensed Wrigley was a small puppy..and played with him by laying down and letting Wrigley do whatever. He still does that. Wrigley crawls all over him !! They truly do get along so well. It is such a blessing. Zeb will even go to the toy chest..dig for a certain toy ( with his nose)..and give it to Wrigley.
I'll have to post a video sometime ( can you post videos on here?)

Anyway... like you mentioned..your Cav. may just be at the age that too much activity hurts him..so a playful puppy may take some getting used to.

Can I say something? I am a huge animal lover...so my love for one breed isn't stronger than another.
I absolutely love our Cavalier. Wrigley has the sweetest little personality. Loves people..other dogs..you name it.
He is extremely affectionate & wants to snuggle. He has been a joy
BUT..and some may find this funny...so does our labrador (Zeb)!
He may be 108 lbs. ( yeah..he is a BIG boy)..but he has the most laid back personality...and he too loves everybody & everything. They BOTH are lap dogs & snugglers....
..we love them both and do not know what life would be without them !!