The episode starts off with the American countdown clock.
This shot while it appears to be Sentai footage, I don't believe it is. The background however may be Sentai footage but the Time Ship design doesn't exactly match with the Timeranger design.
The shot of the time hole opening up while in the same shot as the Time Ship is indeed Sentai footage.
The shot of the Time Sihp's engine igniting with fire, that appears to be new.
Even the Ship's take off (or lift off) is new footage however as soon as you see it as if it's directly close to the time hole: kind of like as seen here then that is when it goes back to Sentai footage.
However the shots of the hole closing would be new.
It then cuts back to the Sentai Giant footage between Doomtron and Q-Rex Dino Mode.
This shot is new footage.
However it then cuts back to Sentai footage as soon as you see a close-up of the Quantum Ranger.
These shots   are back to Sentai footage.
Doomtron leaves in Sentai footage. It then cuts to a bunch of debris which is new footage.
After Eric gets out of the debris and looks up, you'll see a quick Sentai shot of the Q-Rex.
Once you see the C-bots then it's back to new footage.
There's a recycled Sentai shot of Doomtron fires its laser beam.
I shouldn't have to tell you what Year 3000 stuff is Sentai and what isn't Sentai since we've already been through it.
Once you see the C-bots again then it's back to new footage.
There's a Sentai shot of a opened time hole/vortex.
There's another time vortex that opens up and then you'll see the Clock Tower. The following C-bot shot is new footage.
Yes, once you see the C-bots again, they're new footage due to being in the same shot as Wes. It's not 1 of their editing tricks.
Here's a shot of the Memory Adaptation Controls
Once you see Doomtron again (and not to mention the vortex that is opening up in the same scene) then that is when it goes back to Sentai footage.
I'm not sure about this shot it could go either way
However the following shot is definitely Sentai footage.
The finishing shots of the Red Ranger continuing to fight off C-bots is Sentai footage.

Sentai footage comes from Time Episodes 48 and 49