I'm working on the dizzy combo as well, this one in particular
I have found double tapping the TNTs and buffering
between the doubletaps really helps with clean inputs, so inputs look like this with display on
I get the perfect TNT every time due to this.
However I am having a hard time understanding the juggle count at the end (after burning both drive bars and using TNT for a couple hits then jump
for dizzy). Sometimes I'll get the TNT to hit, sometimes it wont, sometimes I'll get one hit but not 2 before the 214 and be unable to jump D, sometimes I'll get it all, but it's hard to figure out WHY exactly.
I was thinking maybe it has something to do with how many hits of TNT they get hit by at the end, but it's not easy to test so if anyone has come across this issue before please share some information as I am so close to getting this dependably every time.
EDIT: My problem was I was not mashing out TNT fast enough at the end (for the final part, doubletapping disrupted my rhythm!), I'm now hitting this combo with ~75% accuracy. Still working on getting a clean launch after the 2nd hit of TNT, but at that point it's a reset to stun anyways so dropping it isn't the worst thing on the planet.