Tracking can be done in many ways. We like to keep the tracking data as light as possible to be able to render the videos quickly.
Track in the final resolution if possible. When delivering 1080p files, try to convert your '8k' footage to 1080p before tracking, and paste it into a 1080p composition within AE.
Use Mocha for tracking, creating masks and rotoscoping.
Export tracking data, masks and shapes from Mocha to AE converting to regular Corner Pin data, Shape data or regular masks over a (pre)composition.
Corner Pin data is easilly pasted on to a composition. Mind where your playhead is when pasting in the data.
Masks are easilly added when exported as shape data from Mocha. Make sure you insert the mask through ‘Edit -> Paste Mocha mask’.
Mocha's exported data usually yields the fastest rendering result and is still extremely powerful and versatile.