Yes, that is DEFINITELY something you should be worried about. Just because you think you can tolerate 20mgs of clonazepam, there is no way you should ever be taking that much meprobomate on top of the clonazepam. Half that dose of meprobomate is enough to make it impossible for you to walk. There's a good chance you'll experience truly horrible ataxia just from the meprobomate.
Such insane dosages of both of those drugs are not necessarily going to be predictable. Honestly, I'd be worrying about possibly dying with those dosages of such strong drugs.
Please be careful. Christ.