Yeah, despite heroin's potency, the high is actually kind of subtle and delicate in many ways, not just all nodding out and drooling on yourself...which if you're chasing that kind of "high" every time you use, you may not be long for this earth..
One "bad day" with heroin, could be your last. There's not much margin for error. If you have to use benzos at all, take a low dose on the tail end of the dope high, but if you start doing that all the time, you'll have two physical addictions to deal with...Of all the 15+ years I used heroin on and off, I never really mixed it with benzos until the last year I was using heroin daily, 2011. It was really what led to me quitting and going to rehab, because it created so many problems in such a short period of time, it made it impossible for me to maintain anymore! And I was maintaining a hundreds of dollars a day habit for me and my GF while working a full-time job that started at 7AM! Another girl I knew started basically giving me her script for 90 1mg xanax every month, and I was instantly screwed...cost me my job...but I'm lucky it didn't kill me...
I could go on all day with stories of people who died, suffered permanent brain damage...which is another horrible fate waiting to happen to you. You OD, live, but are never the same again because you went too long with too little oxygen reaching your brain...It's just not worth the risk, at all!