Welcome to the boards of SCS
Where do you want to store them? On your desk, on a shelf...that will decide the size of the container.
How you sort imho should be by how you think of it-do you think of a color first or the size first? The good news is that wont be in stone so you can always change it up later
I have mine in hard clear plastic rectangle boxes w no lid-very similar to JMs' fridge bins but cheaper at TJ Maxx/Marshalls. I keep them on my work desk.
I cut up the cheap 2/buck thin floppy plastic cutting boards into dividers-I actually do that for a number of things-and label them.
I sort by size, function and then mfg. I generally only have white, ivory and black in these bins. Colors have their own box elsewhere. I dont make them anymore in advance. When those are gone I wont do that again. I just fell into a big batch on clearance at my LSS.
So a label could read A2 WC pratice Canson XL
I only keep a few premade cards ready. If I am going to do a big holiday run, I make the bases then.
See you around!