Make one drop down configure 3 others

I've attached a print screen of what i'm trying to do.

Each of the "test"s in the big drop down gives a different ratio to the 3 percentages.

But note that they're not just 3 cells, they're 3 drop down lists.

I can easily make the test presets make a number appear in a cell, but not when it's a drop down list. Well, like i say, i can even do that but when i then manually go in to change said drop down list (from say 40% to 50%) all that code disappears.

Any ideas?