I find benzos mask withdrawals and cravings. Couldn't care less about heroin since I started eating nitrazepam/bromazepam, even if I don't really get high. I know this is not a plausible solution since they are addictive themselves, but since you are not addicted to them at the moment you could perhaps use them to reduce and eventually kick the heroin in a manner that doesn't get you hooked on benzos instead.