The only time you should be using a BLO mix, is for the first application of the concoction. It helps the mix penetrate deeper into the wood, but, once the first coat has dried, you should only use regular BLO or some other sort of finish. After the first coat has dried and set up the wood, extra coats won't penetrate beyond the first coating. What your doing is trying to build up the finish, diluted finishes take a longer time or more coats to build up the finish. So, it doesn't make much sense to keep applying the diluted mixture, you would be better of applying a finish that isn't broke down/diluted.
Len