Something I have found that helps me is to purposefully introduce small stutters into your speech. It tricks the brain into feeling like you have control because you're doing the stutter on purpose. It reduces tension and makes it less likely that you will run into a hard block. I combine that with easy onset at the beginning of a phrase, so breathing in with a belly breath and letting the air out as you slide into the first word, followed by the "bounces" or purposeful stutters throughout each phrase. This might not make sense, if you need more help i'd be happy to try to explain more in-depth. Best of luck! I'm a hard blocker too, its probably the hardest form of stuttering to modify.