Lynda,
EMB threads multiply like rabbits and you will soon have a bunch! You are wise to consider a storage plan in the early stages.
I started with the 12x12 plastic bins and the white thread holders but soon out grew them. Each tray holds 18 spools and two of them fit into these bins.
https://www.sewforless.com/item/Isac...ls_/12298/c272
Now, I use one the wire basket units from con*tainer store with the smaller height drawers for threads. Each drawer is lined with white erase board cut to size. Then I hot glued white golf T's in a grid and each spool sits on a T. Each drawer holds 81 spools.