make sure the check valve on the booster works GREAT and doesnt leak down. pull it and do the old suction test (use your mouth and suck abnd blow- make sure it isnt leaky).

second, learn to drive differently. engine make lits of vacuum on cruise and deceleration. when you take your foot off the gas and let the engine brake, it makes A LOT of vacuum that the booster will store.

finally, get a vacuum resevoir and install it. i have 6-7" of vacuum at idle and brakes havent failed me yet.