I would doubt that dillution is going to work for you but don't give up.
Eat a high fiber diet with metamucil up to 3 days before the UA then switch to a high fat red meat diet. Continue to home test yourself every couple of days to see how you're doing.
And have a backup plan. Synthetic Urine. QuickFix still works fine. You won't be observed. So pickup a bottle and practice with it to keep the temp right.
So if you're not clean by UA time just sub.
If you do get clean still use some dillution the morning of the UA to give yourself a little added insurance.