Sounds like you could benefit from the
Personal Assistent addon. You can set it up to automatically deposit/withdraw items, and it allows for setting amounts that you can then fill up. Like always keeping a stack of 200 in the bank, and then the profiles will deposit/withdraw accordingly.
For example, I have an alt that holds all blacksmithing mats but I do max level writs on my main as well. So that alt withdraws all blacksmithing mats that everyone else deposits, but has an exception rule that says 'Rubedite Ingot / backpack / == 0'. This way the ingots stay in the bank for my main to craft writs with.