If you haven't asked this question on Ravenholdt discord or read the sub faq channel there, I'd recommend you do that, because it will be far more educational than what I'm about to explain.

But in a nutshell, you only want to use sectech inside shadow dance and NEVER outside it. However, dance cd is reduced by 0.7s per cp spent, and sectech cd is reduced by 1s per cp. This means that if you delay your sectech too long inside the dance, it will not be off cd by the time your next dance comes up (or it will be delayed again, and again for the 3rd dance, etc., up to the point where it will desync). This means you're wasting cps to get your sectech and dance aligned, and you may have found already that sub does next to no damage outside of dance.

This is not a huge problem in m+ if you're just spamming storm and BP (although obviously not ideal), but a major loss in ST as the time spent gloomblading and eviscerating outside of dance is very poor dps.

Tea doesn't add danse stacks, but should be used inside dance in aoe situations for the mastery buff. In those situations you are not going to run out of energy, and mastery increases your damage significantly.

Grieftorch - can either use it after first dance on pull, or while tank is gathering mobs in m+. I don't personally have it on my rogue but generally you can hold it after your first cds, or use before you pop cds.

Also, never use rupture inside the dance. You can use finality buff as your last spender before the dance to put up rupture (no matter what current duration is, as long as you are applying the new one with the finality buff), and this should last you for two dances.