That's good news... I have dual carbs from Langon with my booster setup as well, and I have a split vacuum line for PCV and booster, but no problems with that arrangement. Your idle vacuum is on the low side, though...so I'm guessing that maybe you have a non-stock camshaft in there? If you still have the vacuum powered wipers (I don't), and that system is leaking, I believe that that can cause a vacuum loss. Hopefully somebody more familiar with the stock wiper system and having it leak can speak up?
Anyway, the section of a different PCV (they are calibrated differently) valve might allow you to split the vacuum line for your brakes- the one that you have in there now might have too large of a calibrated leak.
