The smallest QC is the 10000.
The 5000 (round and the slim) are 2A input and 2A output.
The mini are 1A input and 1A output.
I have the 5000 Slim and its a good pocket type solution for charging whilst in your pocket. I got "in the post" a "free gift" of the 5000 round.
I'd say focus on the 10000 - The "speed" type for capacity+speed.